How to get quicker hot water

[Nowizard]

We have recently moved from a large house with three hot water heaters that supplied instant hot water throughout the house to a more conventional house with two, typical, hot water heaters. The time to obtain hot water is greater and varies depending on the distance from the heaters. This is an inconvenience for places such as the kitchen sink, MBR shower and sink. Though not interested in installing a complete system, there are smaller devices that can be installed in selected places. Any comments on the experience of those who have them, approximate cost and other ways the above might be accomplished would be greatly appreciated.

Tim

[WJW]

Installing a hot water recirculating pump on your water heater would be the least expensive option. Obtain quotes from a reputable local plumber for cost.

[RickBoglehead]

There are various devices as you note. All are energy in-efficient.

A hot water recirculating pump puts warm water into the cold water line, so you have to run the cold water longer to get cold water. Of course it also makes the water heater run more. Using a timer incorporated into the system makes it more efficient, but it's still running the water heater longer.

Systems like this are $200 or less, plus installation.

Insulating any exposed hot water pipes can also help things, but much of the piping is not exposed and can't be insulated.

It will be interesting if anyone posts solutions with actual energy impacts.

[Nowizard]

Are you assuming that all faucets would have smaller heaters installed or only three at the most?

Tim

[cheese_breath]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

[Brianmcg321]

Installing a hot water recirculating pump on your water heater would be the least expensive option. Obtain quotes from a reputable local plumber for cost.

My FIL had one of those on his house. It was a $$$$ hog. Your basically recirculating hot water throughout the house. He shut it off after about two months and a couple of nose bleed power bills.

[bob60014]

A former neighbor used this type of recirculation system that he said work well. If I recall the cost was under $300.

https://us.grundfos.com/products/find-p ... up-10.html

[AlohaJoe]

I have small, instant hot water heaters installed in every bathroom in our house. You can easily go online and look up the prices. We paid under $100 each but your costs might vary.

It does what I expect it to do. Beyond that I'm not sure what you're looking for when you ask about "experience".

[TomatoTomahto]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

[TomatoTomahto]

There are various devices as you note. All are energy in-efficient.

A hot water recirculating pump puts warm water into the cold water line, so you have to run the cold water longer to get cold water. Of course it also makes the water heater run more. Using a timer incorporated into the system makes it more efficient, but it's still running the water heater longer.

Systems like this are $200 or less, plus installation.

Insulating any exposed hot water pipes can also help things, but much of the piping is not exposed and can't be insulated.

It will be interesting if anyone posts solutions with actual energy impacts.

I believe that there are two types: one that, as you say, puts warm water in the cold water line, and another system (required by code in our town for all hot water users more than n feet from the hot water heater) that has a hot water return line. So, the recirculating pump moves the hot water out along the trunk and doesn’t mix hot and cold.

It can use a lot of electricity; in my case, a moot concern.

[RickBoglehead]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

We have our own well, and an 80 gallon gas hot water heater. Yes, we have to run the shower for 60 seconds (edit - timed it) to get hot water, because our shower is the furthest thing from the tank. Since we have a septic system, all waste water goes back to the ground and isn't going to a water treatment plant, so we're not going to change here.

Our future retirement location may have public water, and septic, so we'll have to evaluate the most efficient way to use our utilities. We'll also consider solar, may be more cost effective in 2 years and in a southern state.

[BIGal]

Installing a hot water recirculating pump on your water heater would be the least expensive option. Obtain quotes from a reputable local plumber for cost.

My FIL had one of those on his house. It was a $$$$ hog. Your basically recirculating hot water throughout the house. He shut it off after about two months and a couple of nose bleed power bills.

We have a recirculating pump (I installed) https://www.amazon.com/gp/product/B000E ... UTF8&psc=1 back in 2013 that solved the same issue for us. Ours has a built-in timer so it does not run constantly. I believe that our electric bill AND water bills actually decreased after installation (we have an electric WH). Maybe your FIL should check to see if he has a timer and could run the unit a couple of hours in the am and pm when hot water is normally used.

[lthenderson]

A device not mentioned that can reduce the amount of cold water wasted is installing thermostatic valves. We have them in our showers and they are great. You still have to wait for the cold water in the pipes to exit but it eliminates any time adjusting the hot and cold knobs to get the perfect shower temperature. Once the valve is set to your desired temperature, once it gets hot water it instantaneously adjust it to your perfect temperature. Also if someone flushes or kicks on the clothes washer while you are in the shower, the pressure will reduce somewhat but the temperature will remain exactly the same so there are no surprises.

[TomatoTomahto]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

We have our own well, and an 80 gallon gas hot water heater. Yes, we have to run the shower for probably 90 seconds to get hot water (never timed it), because our shower is the furthest thing from the tank. Since we have a septic system, all waste water goes back to the ground and isn't going to a water treatment plant, so we're not going to change here.

Our future retirement location may have public water, and septic, so we'll have to evaluate the most efficient way to use our utilities. We'll also consider solar, may be more cost effective in 2 years and in a southern state.

We also have wells and septic. I have no idea how water flows underground, so I just consider water "down the drain" literally. I wouldn't doubt that a good bit of it returns to our well, so I take your point.

[cheese_breath]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

This wasn't meant as criticism of OP's post, just a comment on how blessed we are in this country.

[samsoes]

Agree, wholeheartedly.

I've gone on rural missionary trips to a few impoverished countries, and clean water is a huge concern for these folks.

[flossy21]

I have one of these Chili Pepper units installed in our Master Bath which is on the far side of the house from where the hot water heater is located. The plumbing is easy but you need to have an outlet to plug it into. I put an outlet under the sink just for this unit. My local municipality offered a $50 rebate for buying the unit at the time as well.

https://chilipepperapp.com/

The way it works is that it pumps the water from the hot side down the cold side until it senses hot water. No water gets sent down the drain because it is a closed system.

[BuddyJet]

There are various devices as you note. All are energy in-efficient.

A hot water recirculating pump puts warm water into the cold water line, so you have to run the cold water longer to get cold water. Of course it also makes the water heater run more. Using a timer incorporated into the system makes it more efficient, but it's still running the water heater longer.

Systems like this are $200 or less, plus installation.

Insulating any exposed hot water pipes can also help things, but much of the piping is not exposed and can't be insulated.

It will be interesting if anyone posts solutions with actual energy impacts.

Per the Grundfos brochure, the pump uses 25 watts max when running so the power impact is less than $7.50 per month if set to run 12 hours a day. YMMV based on power cost and runtime settings.

https://us.grundfos.com/content/dam/NAM ... System.pdf

BTW, I run Grundfos in all my houses for recirc and boilers and have found them to be the most reliable pumps.

[Bir48die]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

This wasn't meant as criticism of OP's post, just a comment on how blessed we are in this country.

Totally agree but it was off topic

[RickBoglehead]

There are various devices as you note. All are energy in-efficient.

A hot water recirculating pump puts warm water into the cold water line, so you have to run the cold water longer to get cold water. Of course it also makes the water heater run more. Using a timer incorporated into the system makes it more efficient, but it's still running the water heater longer.

Systems like this are $200 or less, plus installation.

Insulating any exposed hot water pipes can also help things, but much of the piping is not exposed and can't be insulated.

It will be interesting if anyone posts solutions with actual energy impacts.

Per the Grundfos brochure, the pump uses 25 watts max when running so the power impact is less than $7.50 per month if set to run 12 hours a day. YMMV based on power cost and runtime settings.

https://us.grundfos.com/content/dam/NAM ... System.pdf

BTW, I run Grundfos in all my houses for recirc and boilers and have found them to be the most reliable pumps.

Isn't that missing the cost to heat the water? You've got the cost to run the pump which sends the lukewarm water back to the water heater, but not the cost to run the water heater to keep that water hot.

[forgeblast]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

We have our own well, and an 80 gallon gas hot water heater. Yes, we have to run the shower for probably 90 seconds to get hot water (never timed it), because our shower is the furthest thing from the tank. Since we have a septic system, all waste water goes back to the ground and isn't going to a water treatment plant, so we're not going to change here.

Our future retirement location may have public water, and septic, so we'll have to evaluate the most efficient way to use our utilities. We'll also consider solar, may be more cost effective in 2 years and in a southern state.

We also have wells and septic. I have no idea how water flows underground, so I just consider water "down the drain" literally. I wouldn't doubt that a good bit of it returns to our well, so I take your point.

Our well is on one side of the house our septic on the down slope away from the well. We still test the water every couple of years and run a UV light system on the well water.

[Texanbybirth]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

You can always just hop in the cold shower, or start shaving etc, while the water heats up. That way none of the water is wasted.

[Luke Duke]

https://chilipepperapp.com

[TomatoTomahto]

A post like this reminds me of how blessed we are in America. We worry about getting instant hot water while much of the world worries about getting drinkable water.

Yes, BUT some of us worry about wasting water while waiting for it to heat up. As I explained to our plumber when I increased the power on the recirculating pump: our solar panels give us almost unlimited electrons for essentially free, our wells are much more limited.

You can always just hop in the cold shower, or start shaving etc, while the water heats up. That way none of the water is wasted.

I paid for solar panels in part so that I don't have to take a cold shower.

Back OT, in my experience, if you have a properly sized hot water return and recirculating pump, you can have hot water with minimal waste (of electrons, time, or water).

[Nowizard]

I mentioned in a response to Cheesebreath that this was a first world issue. I often mention that with posts but did not here for some reason. We had reasonable utility bills with our prior house with recirculating hot water. I do feel we are extremely fortunate and react to many posts in that manner. This site is very helpful in that it responds carefully and thoughtfully to many different types of investors and responses. It is another fortunate thing in our lives!

Tim

[Big Dog]

we solved the hot water speed problem in the kitchen by upgrading to a dishwasher that warms its own water. (our kitchen is far away from the HW heater.)

[mpnret]

When the plumber installed my Boiler/Hot Water Heater he added a small bronze circulator pump with a dedicated recirc line. Instant hot water and no hot water in cold line. The recirc line runs from the furthest point of the hot feed line back to the water heater. Hot water feed line (1") and recirc line (1/2") are both insulated so you can think of the both lines as an extension of the hot water tank. The pump slowly circulates the hot water continually in the insulated loop. I can't remember the exact current draw of the pump but back when he did this I calculated it was so low a timer wasn't necessary. This setup has been running almost non-stop for 32 years and works great.
I did realize at one point if I shut off the pump the water continues to circulate just by gravity but every month or will reach some ideal conditions to make circulation stop and I have to turn on the pump again to get things started. So I just leave the pump on all the time.

[TN_Boy]

There are various devices as you note. All are energy in-efficient.

A hot water recirculating pump puts warm water into the cold water line, so you have to run the cold water longer to get cold water. Of course it also makes the water heater run more. Using a timer incorporated into the system makes it more efficient, but it's still running the water heater longer.

Systems like this are $200 or less, plus installation.

Insulating any exposed hot water pipes can also help things, but much of the piping is not exposed and can't be insulated.

It will be interesting if anyone posts solutions with actual energy impacts.

Unfortunately, we did not measure the cost (in water or electricity) of the recirculating pump solution. But we have one, to solve the issue of having to run water a long time to get a hot shower. It does have a timer, so you can turn it off when unlikely to need it. We are extremely happy with the result.

For the kitchen, we have one of those instant hot setups (small hot water heater under the sink). So we get hot (about 160 degrees) water immediately there.

[HomeStretch]

Similar issue when we moved in as the hot water heater is on the opposite side of the bedrooms/bathrooms in our older multi-story house. We had a new furnace, hot water heater and shower thermostatic valves installed, and the plumber ran larger pipes from furnace/water heater across the exposed cellar ceiling (half the distance to the bathrooms) but couldn’t do more as pipes went into the floors/walls after that. Helped but still took ~5-10 minutes (especially in winter) to get hot water to comfortably shower in the upper level. A closed loop recirculating system wasn’t possible so we installed the little recirculating device 20 years ago mentioned above to the sink pipes in the farthest bathroom. Significant improvement. Highly recommend. Have not noticed a large electrical bill increase but don’t care as hot showers on demand are priceless.

[targetconfusion]

I did realize at one point if I shut off the pump the water continues to circulate just by gravity but every month or will reach some ideal conditions to make circulation stop and I have to turn on the pump again to get things started. So I just leave the pump on all the time.

Interesting.. is it something like this happening? https://en.wikipedia.org/wiki/Thermosiphon
I'm sure greater minds that mine have considered this but if the thermal gradient has enough energy to circulate the hot water slowly it seems like a potential low-cost and -maintenance solution to this common problem. Maybe even possible to rig such that the pump kick-start is unneeded.

[neilpilot]

Similar issue when we moved in as the hot water heater is on the opposite side of the bedrooms/bathrooms in our older multi-story house...... and the plumber ran larger pipes from furnace/water heater across the exposed cellar ceiling (half the distance to the bathrooms) but couldn’t do more as pipes went into the floors/walls after that.

Actually, larger pipes will typically result a longer wait for hot water and more wasted water, since there's more cold stagnant water to displace and more pipe mass to bring up to temperature.

[MathWizard]

I had an electrician add a switched outlet under our sink.
The switched outlet is the same as the light above the sink, and that is where the
recirculating pump is connected.

When we want to use the dishwasher or wash dishes by hand, we flip the switch
about 10 minutes before we want the hot water. We never noticed a change in costs.
We have a Nat gas water heater, so having fully hot water going into the
dishwasher eliminates it using the built-in heating element, which is expensive.

I'd have preferred to have a hot water return line, but that
was not feasible, so it connects to the cold water line.

I also had a switched outlet installed at the same time (no extra cost) in case my
switched idea did not work, then I'd have used a timer.

[WhiteMaxima]

I turn on hot water when I brush my teeth. There is always cold water in the pipe. When I finish brushing. The water become warm for shower. To saving water, you can collect used water to flush toilet if you are BH.

[mpnret]

I did realize at one point if I shut off the pump the water continues to circulate just by gravity but every month or will reach some ideal conditions to make circulation stop and I have to turn on the pump again to get things started. So I just leave the pump on all the time.

Interesting.. is it something like this happening? https://en.wikipedia.org/wiki/Thermosiphon
I'm sure greater minds that mine have considered this but if the thermal gradient has enough energy to circulate the hot water slowly it seems like a potential low-cost and -maintenance solution to this common problem. Maybe even possible to rig such that the pump kick-start is unneeded.

It looks like this (thermosiphoning) is exactly whats happening. Maybe someday I will have time to troubleshoot this further. It most likely if certain conditions are met certain actions are taken (thermosiphoning stops) like running 2 baths at once or whatever.

[TN_Boy]

I turn on hot water when I brush my teeth. There is always cold water in the pipe. When I finish brushing. The water become warm for shower. To saving water, you can collect used water to flush toilet if you are BH.

This doesn't work if, say the hot water heater is on the other side of the house and the hot water has to run all the way through a bunch of plumbing. I know this because our house is plumbed like that. I'd say to get hot water with just a faucet would take five minutes in our house. That might be enough time.

I turn off the tap when brushing to save water myself

[mpnret]

I turn on hot water when I brush my teeth. There is always cold water in the pipe. When I finish brushing. The water become warm for shower. To saving water, you can collect used water to flush toilet if you are BH.

This doesn't work if, say the hot water heater is on the other side of the house and the hot water has to run all the way through a bunch of plumbing. I know this because our house is plumbed like that. I'd say to get hot water with just a faucet would take five minutes in our house. That might be enough time.

I turn off the tap when brushing to save water myself

Every house is different. If you have a open basement with a hot water feed line running the length of it adding a recirc line w/recirc pump as I described above would do it. Open means you could run a recirc line and also insulate both pipes. The recirc line doesn't have to go all the way to the last bath on the line. Just as far as you can go. Pro: Most convient and worry free once it's installed. Mine is untouched for 32 years. Con: you need to run a line all the way back to the water heater and insulate both the feed an return. Also the cost of the return line. Mine is copper which was cheap 32 years ago. You would most likely use PEX if running that line today. If you don't have a open basement use the chilipepper or similiar solution in a few of the above posts. Not as convient to use. A little more energy loss being you are pushing some warm water back down the cold water line but you are not wasting water as if you were opening the faucet to get warm water.

[TN_Boy]

I turn on hot water when I brush my teeth. There is always cold water in the pipe. When I finish brushing. The water become warm for shower. To saving water, you can collect used water to flush toilet if you are BH.

This doesn't work if, say the hot water heater is on the other side of the house and the hot water has to run all the way through a bunch of plumbing. I know this because our house is plumbed like that. I'd say to get hot water with just a faucet would take five minutes in our house. That might be enough time.

I turn off the tap when brushing to save water myself

Every house is different. If you have a open basement with a hot water feed line running the length of it adding a recirc line w/recirc pump as I described above would do it. Open means you could run a recirc line and also insulate both pipes. The recirc line doesn't have to go all the way to the last bath on the line. Just as far as you can go. Pro: Most convient and worry free once it's installed. Mine is untouched for 32 years. Con: you need to run a line all the way back to the water heater and insulate both the feed an return. Also the cost of the return line. Mine is copper which was cheap 32 years ago. You would most likely use PEX if running that line today. If you don't have a open basement use the chilipepper or similiar solution in a few of the above posts. Not as convient to use. A little more energy loss being you are pushing some warm water back down the cold water line but you are not wasting water as if you were opening the faucet to get warm water.

We have the recirculating pump described above (the grundfos) and it works very well. Have not seen a problem with cost for this solution. It was economical to install, has a timer, and works well. It's extremely convenient, so I'm not sure about your comment there. It runs without intervention. Saves us from running a lot of cold water to get a hot shower.

The way our house is constructed, the recirc line would have been much more expensive.

[michaeljc70]

Taking the normal setup I've seen, a recirculating pump under a bathroom sink will get hot water to the sink. You will still have to wait for hot water in the shower albeit less time because there is hot water closer by. You will typically still have cold water from the trunk line to the shower.

It probably takes 30 seconds to get hot water in my shower or kitchen sink if no fixtures have been used close by. Acceptable to me. A few things I do is:

-turn the water to hot to brush my teeth. The water is cold, but pulling hot water closer to the bathroom.

-Wash any hand wash items before running the dishwasher. This gets hot water to the kitchen so the dishwasher doesn't have to heat the water. The manual for my dishwasher (Bosch) recommends running the hot water close to the dishwasher to save electricity (I have a gas water heater).

-Run the garbage disposal in the sink before the dishwasher using "hot" water. This gets hot water to the kitchen without wasting it.

-If it needs it, I will spray the shower (all tile/glass) with cleaner and let it work while I brush my teeth, take my pills, etc. Then I will use the hand shower on hot to wash away the cleaner (giving it a scrub with a brush here and there as needed). By the time I am done the water is hot.

[mpnret]

I turn on hot water when I brush my teeth. There is always cold water in the pipe. When I finish brushing. The water become warm for shower. To saving water, you can collect used water to flush toilet if you are BH.

This doesn't work if, say the hot water heater is on the other side of the house and the hot water has to run all the way through a bunch of plumbing. I know this because our house is plumbed like that. I'd say to get hot water with just a faucet would take five minutes in our house. That might be enough time.

I turn off the tap when brushing to save water myself

Every house is different. If you have a open basement with a hot water feed line running the length of it adding a recirc line w/recirc pump as I described above would do it. Open means you could run a recirc line and also insulate both pipes. The recirc line doesn't have to go all the way to the last bath on the line. Just as far as you can go. Pro: Most convient and worry free once it's installed. Mine is untouched for 32 years. Con: you need to run a line all the way back to the water heater and insulate both the feed an return. Also the cost of the return line. Mine is copper which was cheap 32 years ago. You would most likely use PEX if running that line today. If you don't have a open basement use the chilipepper or similiar solution in a few of the above posts. Not as convient to use. A little more energy loss being you are pushing some warm water back down the cold water line but you are not wasting water as if you were opening the faucet to get warm water.

We have the recirculating pump described above (the grundfos) and it works very well. Have not seen a problem with cost for this solution. It was economical to install, has a timer, and works well. It's extremely convenient, so I'm not sure about your comment there. It runs without intervention. Saves us from running a lot of cold water to get a hot shower.

The way our house is constructed, the recirc line would have been much more expensive.

My not as convenient comment came mostly from the fact that the chilipepper has a button that you have to push and the Grundfos system has a timer and they both operate by pushing warm water back to the water heater in the cold water feed line so now you have warm water in your cold water faucet. So not as convenient but still what I would do if I didn't have a recirc line.

[michaeljc70]

In reading the reviews for Chillipepper on Amazon there are many comments on the item failing after not too long periods of time.

[FrugalInvestor]

Installing a hot water recirculating pump on your water heater would be the least expensive option. Obtain quotes from a reputable local plumber for cost.

My FIL had one of those on his house. It was a $$$$ hog. Your basically recirculating hot water throughout the house. He shut it off after about two months and a couple of nose bleed power bills.

We have a recirculating pump. Since we're retired and don't have a set schedule it was difficult to set the timer so it was running when we needed the hot water and not running when we didn't (creating the larger than normal electric or gas bills you mention). The solution I found is to use a smart plug for the pump. We now just tell Alexa to "turn on the hot water" about 5 minutes before we need it and to turn it off when we head for the shower. Problem solved!

[michaeljc70]

Installing a hot water recirculating pump on your water heater would be the least expensive option. Obtain quotes from a reputable local plumber for cost.

My FIL had one of those on his house. It was a $$$$ hog. Your basically recirculating hot water throughout the house. He shut it off after about two months and a couple of nose bleed power bills.

We have a recirculating pump. Since we're retired and don't have a set schedule it was difficult to set the timer so it was running when we needed the hot water and not running when we didn't (creating the larger than normal electric or gas bills you mention). The solution I found is to use a smart plug for the pump. We now just tell Alexa to "turn on the hot water" about 5 minutes before we need it and to turn it off when we head for the shower. Problem solved!

Good idea.

As I said above, I just run the water. If you have a 3/4" trunk line and the shower is 35 feet from the water tank, the pipe is only holding .8 gallons of cold water that you need to get rid of. People that have to wait 90 seconds must have extremely long lines to their bathroom or very low flow showers/faucets.

[FrugalInvestor]

Installing a hot water recirculating pump on your water heater would be the least expensive option. Obtain quotes from a reputable local plumber for cost.

My FIL had one of those on his house. It was a $$$$ hog. Your basically recirculating hot water throughout the house. He shut it off after about two months and a couple of nose bleed power bills.

We have a recirculating pump. Since we're retired and don't have a set schedule it was difficult to set the timer so it was running when we needed the hot water and not running when we didn't (creating the larger than normal electric or gas bills you mention). The solution I found is to use a smart plug for the pump. We now just tell Alexa to "turn on the hot water" about 5 minutes before we need it and to turn it off when we head for the shower. Problem solved!

Good idea.

As I said above, I just run the water. If you have a 3/4" trunk line and the shower is 35 feet from the water tank, the pipe is only holding .8 gallons of cold water that you need to get rid of. People that have to wait 90 seconds must have extremely long lines to their bathroom or very low flow showers/faucets.

Yes, it sounds like you have a very short run, my master bath requires at least 2 minutes and one of the guest baths takes longer than that.

Also, I think that most of my increased cost is attributable to energy for heating the water rather than water loss. Since the pump is circulating the heated water through hot water lines for the entire house that total volume needs to be heated for the entire time that the pump is on. On top of that the water lines are not insulated like a water heater so are losing much of that heat. That energy cost can add up particularly if you leave the pump on during times you may not be using it (which happens with a timer). The smart plug reduces much of the waste providing you remember to tell it to turn the water off.

[michaeljc70]

Installing a hot water recirculating pump on your water heater would be the least expensive option. Obtain quotes from a reputable local plumber for cost.

My FIL had one of those on his house. It was a $$$$ hog. Your basically recirculating hot water throughout the house. He shut it off after about two months and a couple of nose bleed power bills.

We have a recirculating pump. Since we're retired and don't have a set schedule it was difficult to set the timer so it was running when we needed the hot water and not running when we didn't (creating the larger than normal electric or gas bills you mention). The solution I found is to use a smart plug for the pump. We now just tell Alexa to "turn on the hot water" about 5 minutes before we need it and to turn it off when we head for the shower. Problem solved!

Good idea.

As I said above, I just run the water. If you have a 3/4" trunk line and the shower is 35 feet from the water tank, the pipe is only holding .8 gallons of cold water that you need to get rid of. People that have to wait 90 seconds must have extremely long lines to their bathroom or very low flow showers/faucets.

Yes, it sounds like you have a very short run, my master bath requires at least 2 minutes and one of the guest baths takes longer than that.

Also, I think that most of my increased cost is attributable to energy for heating the water rather than water loss. Since the pump is circulating the heated water through hot water lines for the entire house that total volume needs to be heated for the entire time that the pump is on. On top of that the water lines are not insulated like a water heater so are losing much of that heat. That energy cost can add up particularly if you leave the pump on during times you may not be using it (which happens with a timer). The smart plug reduces much of the waste providing you remember to tell it to turn the water off.

If the hot water is sent down the cold water line don't you have to wait for the cold water line to be cleared of hot water (assuming you are using a mix of hot and cold water)? I cannot take a shower using only my hot water (too hot).

[FrugalInvestor]

If the hot water is sent down the cold water line don't you have to wait for the cold water line to be cleared of hot water (assuming you are using a mix of hot and cold water)? I cannot take a shower using only my hot water (too hot).

I'm not a plumber but there are separate hot and cold water lines. The hot water is only coming from the hot line. The mixing for warm water is done in your shower (or sink) faucet valve. The water cools in the hot water line over time when it's not being used and the circulating pump fills that line with hot water before you turn on the faucet.

[michaeljc70]

If the hot water is sent down the cold water line don't you have to wait for the cold water line to be cleared of hot water (assuming you are using a mix of hot and cold water)? I cannot take a shower using only my hot water (too hot).

I'm not a plumber but there are separate hot and cold water lines. The hot water is only coming from the hot line. The mixing for warm water is done in your shower (or sink) faucet valve. The water cools in the hot water line over time when it's not being used and the circulating pump fills that line with hot water before you turn on the faucet.

I think you are right. The "hot" water that is no longer hot is sent back to the tank via the cold water line so it would likely be room temperature and not hot I guess.