UPDATE-Best way to heat basement?

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fortfun
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UPDATE-Best way to heat basement?

Post by fortfun » Sun Jan 13, 2019 10:56 pm

SEE UPDATE at Bottom of the thread.
Just got an Ecobee3 lite thermostat with 2 sensors. Basement is 11 degrees cooler than first and second floor. Our house has forced air via furnace. We also have solar panels that generate enough electricity to meet our regular electrical needs but no more. Has anyone done the math on these options:

1. Close some of the upper vents and bump up the heat until the basement reaches a suitable temperature. I've read that it isn't a great idea to close many vents in a forced air system because it can damage the furnace.
2. I installed a gas fireplace when I finished the basement. I know it isn't super efficient but maybe it would be cheaper than running the furnace when the rest of the house is warm enough already. I could probably put it on a thermostat. Basement is 1k sq ft. I'm not sure how it would do heating the entire basement.
3. Use space heaters to regulate the temperature. We did this last winter and they used a ton of electricity, so I'm not leaning toward this solution.

Note: The basement is usually occupied and we must leave the door closed to keep pets out.

Thanks for suggestions!
Last edited by fortfun on Fri Jan 18, 2019 10:23 pm, edited 2 times in total.

fire0216
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Re: Best way to heat basement?

Post by fire0216 » Sun Jan 13, 2019 11:12 pm

Can you vent from the furnace room into the basement, meaning keep furnace door open to allow warm air into the basement? This would help heat the basement but not 100%.
Do you have a heat pump (air conditioner exchanger that cools hot air in the summer & HEATS cold air for winter) If no, then maybe you can convert your AC to a heat pump and have that heat your basement.
Another option is to reroute some of your vents to send heated air to the basement. For example, maybe one of your 1st floor has multiple registers. Then maybe close off a register & route that vent to your basement
Another option is to use a vent free gas firelog in a fireplace "area". There is a lot of controversy regarding vent free gas logs, but I use a set in my fireplace without any issues. I have 2 CO sensors (one battery & one hardwired) nearby the fireplace. I also slightly open the fireplace flue to let some gas fumes out.
A fireplace per se is not required for gas logs but does require a fireproof enclosure such as a prebuilt fireplace enclosure. You can also purchase insulated chimney pipe to vent gas heated air outside.

suemarkp
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Re: Best way to heat basement?

Post by suemarkp » Sun Jan 13, 2019 11:57 pm

Why is the basement colder -- is it lack of heat registers (a basement that size should have about six 6" ducts), is it uninsulated, drafty/leaky, and/or have single pane windows?

If the basement is somewhat unfinished, then adding ductwork is easy. You can generally close a few upstairs vents without issue. A better approach is to add more vents to the downstairs and either close 3 or 4 upstairs ones in winter and 3 or 4 downstairs ones in summer. This way your air flow and static pressure drop stay close to what the system is designed for. You can try to reduce the heat loss by adding insulation, installing better windows, and sealing major air leaks (weatherstripping, caulk, making sure vent fans have a damper).

You can add heat to the basement, or reduce heat loss. Both cost money. If you add heat, you need to do the math between the cost per BTU. Resistance heat is 100% efficient, and is 3.412 BTU per watt consumed (i.e. a 1000 watt space heater produces 3412 BTU of heat and 3412 BTU-Hr if it runs for 1 hour). Find your electric rate in KW-Hr to see what 1000 BTU-Hr costs you. Similarly, natural gas is priced in either therms or CCF. Translate this into dollars per 1000 BTU-UR and realize the fireplace is not 100% efficient. Most are 70% to 80% efficient.

Doubling insulation R value cuts the heat loss in half. If you have no insulation in the walls (let's say they are R1) and you put R16 in the walls, the heat lost through the walls will decrease by a factor of 4. Making that wall R32 will reduce the heat loss by a factor of 5 (only a 20% improvement with a cost doubling of the insulation). So you quickly get diminishing returns with insulation and get the biggest bang for the buck in walls that are missing insulation. Same with doors and windows, but it is difficult to make huge gains here. Note that window U value is just the reciprocal of R value (e.g. U = .25 is the same as R4).
Mark | Kent, WA

3504PIR
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Re: Best way to heat basement?

Post by 3504PIR » Mon Jan 14, 2019 12:09 am

Did you set up the basement fireplace for heat or looks? You can generate a lot of heat from having the right box and logs. Do you have a blower on yours?

Can it be converted to regular log burning? Probably not the best option, but worth knowing if it’s vented or non vented.

We have 3 fireplaces, one wood burning, one gas for looks and a gas nonvented in our basement for heat. We have an insert for our wood burner and it also puts off a huge amount of heat.

I’d recommend going to a fireplace store and seeing what you can do (which is a lot) for getting a specific setup for your needs. Additionally, we have our basement on its own system for heat and air. A small Mitsubishi unit for 1000 sf would be another option which has worked well for us.

Ithrive
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Re: Best way to heat basement?

Post by Ithrive » Mon Jan 14, 2019 2:54 am

Doubling insulation R value cuts the heat loss in half. If you have no insulation in the walls (let's say they are R1) and you put R16 in the walls, the heat lost through the walls will decrease by a factor of 4. Making that wall R32 will reduce the heat loss by a factor of 5 (only a 20% improvement with a cost doubling of the insulation). So you quickly get diminishing returns with insulation and get the biggest bang for the buck in walls that are missing insulation. Same with doors and windows, but it is difficult to make huge gains here. Note that window U value is just the reciprocal of R value (e.g. U = .25 is the same as R4).

What does this mean?? Does this mean insulation is pointless??

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Watty
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Re: Best way to heat basement?

Post by Watty » Mon Jan 14, 2019 6:40 am

fortfun wrote:
Sun Jan 13, 2019 10:56 pm
... basement is usually occupied and we must leave the door closed to keep pets out.
Using child gates might be an option.
fortfun wrote:
Sun Jan 13, 2019 10:56 pm
I installed a gas fireplace when I finished the basement.
It would have been better to have planned on how to heat the basement before you finished it since you would have had more options.

You can Google "Ductless Heating" or "mini split systems" which are basically small heat pumps where there is a unit outside the house that is connected to a small unit inside the house that has a fan and heat exchanger. How well these would work would depend on your climate and might not be a good choice if you get heavy snow.

Here is one companies web page on their systems.
https://www.mitsubishicomfort.com/artic ... ng-systems

Installing one of these is probably not a good DIY job for most people but should be pretty easy for a HVAC company.

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TomatoTomahto
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Re: Best way to heat basement?

Post by TomatoTomahto » Mon Jan 14, 2019 7:02 am

Watty wrote:
Mon Jan 14, 2019 6:40 am
You can Google "Ductless Heating" or "mini split systems" which are basically small heat pumps where there is a unit outside the house that is connected to a small unit inside the house that has a fan and heat exchanger. How well these would work would depend on your climate and might not be a good choice if you get heavy snow.
We just installed one for the garage gym and studio. We get lots of snow in MA, but they installed the outdoor unit well off the ground. Nice Wi-Fi app, very quiet, and very efficient.
Okay, I get it; I won't be political or controversial. The Earth is flat.

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fortfun
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Re: Best way to heat basement?

Post by fortfun » Mon Jan 14, 2019 10:07 am

Thanks for the replies everyone. Good suggestions here!

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fortfun
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Re: Best way to heat basement?

Post by fortfun » Mon Jan 14, 2019 10:11 am

suemarkp wrote:
Sun Jan 13, 2019 11:57 pm
Why is the basement colder -- is it lack of heat registers (a basement that size should have about six 6" ducts), is it uninsulated, drafty/leaky, and/or have single pane windows?

If the basement is somewhat unfinished, then adding ductwork is easy. You can generally close a few upstairs vents without issue. A better approach is to add more vents to the downstairs and either close 3 or 4 upstairs ones in winter and 3 or 4 downstairs ones in summer. This way your air flow and static pressure drop stay close to what the system is designed for. You can try to reduce the heat loss by adding insulation, installing better windows, and sealing major air leaks (weatherstripping, caulk, making sure vent fans have a damper).

You can add heat to the basement, or reduce heat loss. Both cost money. If you add heat, you need to do the math between the cost per BTU. Resistance heat is 100% efficient, and is 3.412 BTU per watt consumed (i.e. a 1000 watt space heater produces 3412 BTU of heat and 3412 BTU-Hr if it runs for 1 hour). Find your electric rate in KW-Hr to see what 1000 BTU-Hr costs you. Similarly, natural gas is priced in either therms or CCF. Translate this into dollars per 1000 BTU-UR and realize the fireplace is not 100% efficient. Most are 70% to 80% efficient.

Doubling insulation R value cuts the heat loss in half. If you have no insulation in the walls (let's say they are R1) and you put R16 in the walls, the heat lost through the walls will decrease by a factor of 4. Making that wall R32 will reduce the heat loss by a factor of 5 (only a 20% improvement with a cost doubling of the insulation). So you quickly get diminishing returns with insulation and get the biggest bang for the buck in walls that are missing insulation. Same with doors and windows, but it is difficult to make huge gains here. Note that window U value is just the reciprocal of R value (e.g. U = .25 is the same as R4).
Thanks suemarkp. Much of the difference, at leas in the daylight hours, is due to the passive heating that we get through all of our nice south facing windows. Sadly, turning on the furnace fan doesn't really exchange that heat into the basement. When the furnace is on, the basement is about 3 degrees cooler than the rest of the house. I think I'll add a few more registers down there.

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Re: Best way to heat basement?

Post by bloom2708 » Mon Jan 14, 2019 10:23 am

A few things to consider:

1. Use the Ecobee to run the fan 50 minutes out of each hour. Keep air circulating.
2. Cold air sinks, warm air rises. Nothing we can do about that.
3. The sun shining during the day can keep the main floor and top floors at temperature. The furnace doesn't run. Cold air pools downstairs
4. Do temp averaging with the main floor and basement during the winter.
5. Disable the feature that detects motion in a room and then doesn't use that sensor until occupied.

We have an ecobee3. 2 story house with full basement. 1 sensor upstairs, 2 on main level and 1 in the basement.

In the winter I close all top level vents. Main level and basement vents are open. I use the 2 main level and basement sensors for determining the avg temp. If it is 71, 70 and basement is 68, that makes the average 70. Temp is set to 71 and the system will run. Run the fan 50 to 55 minutes of each hour and keep air moving.

I can keep the basement and main levels right but then the upstairs is 2-3 degrees warmer. Or I can keep the top and main levels right, but then the basement is 2-3 degrees colder. Just as good as it gets without a zoned or multi-furnace home.

In the summer, I close the basement vents and partially open all vents on the main level.All vents upstairs are fully open. I then use the upstairs an 1 main level sensor for temp averaging. Getting cold air upstairs is the problem. It wants to sink back down to the basement.

I've learned that I can only get it so good. We have bedrooms on all 3 levels, so I can't abandon the basement and just allow it to be 10 degrees colder.

Good luck tinkering with your ecboee settings and vents open/partially open/closed. It is a great little device. Add a pack of additional sensors of you have cold spots. Proper venting is important. If the basement doesn't have enough vents and cold air return options, it will be difficult to remedy without adding a new heat source. A mini-split is a good idea. We have considered putting one upstairs to help for cooling in the summers.
Last edited by bloom2708 on Mon Jan 14, 2019 10:42 am, edited 1 time in total.
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barnaclebob
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Re: Best way to heat basement?

Post by barnaclebob » Mon Jan 14, 2019 10:37 am

Ithrive wrote:
Mon Jan 14, 2019 2:54 am
Doubling insulation R value cuts the heat loss in half. If you have no insulation in the walls (let's say they are R1) and you put R16 in the walls, the heat lost through the walls will decrease by a factor of 4. Making that wall R32 will reduce the heat loss by a factor of 5 (only a 20% improvement with a cost doubling of the insulation). So you quickly get diminishing returns with insulation and get the biggest bang for the buck in walls that are missing insulation. Same with doors and windows, but it is difficult to make huge gains here. Note that window U value is just the reciprocal of R value (e.g. U = .25 is the same as R4).

What does this mean?? Does this mean insulation is pointless??
No, it means that adding more insulation isn't cost effective or practical in some instances.

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TomatoTomahto
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Re: Best way to heat basement?

Post by TomatoTomahto » Mon Jan 14, 2019 11:14 am

barnaclebob wrote:
Mon Jan 14, 2019 10:37 am
Ithrive wrote:
Mon Jan 14, 2019 2:54 am
Doubling insulation R value cuts the heat loss in half. If you have no insulation in the walls (let's say they are R1) and you put R16 in the walls, the heat lost through the walls will decrease by a factor of 4. Making that wall R32 will reduce the heat loss by a factor of 5 (only a 20% improvement with a cost doubling of the insulation). So you quickly get diminishing returns with insulation and get the biggest bang for the buck in walls that are missing insulation. Same with doors and windows, but it is difficult to make huge gains here. Note that window U value is just the reciprocal of R value (e.g. U = .25 is the same as R4).
What does this mean?? Does this mean insulation is pointless??
No, it means that adding more insulation isn't cost effective or practical in some instances.
Insulation also isn't always an arithmetical mean of the various R values. For example, we've insulated roughly half of our cathedral ceiling (the flat part) to R60+. The other half, yet to be addressed, is probably R5 on a good day. The net effective insulation isn't R33. Air, heat, and water will find their way in and out of homes.
Okay, I get it; I won't be political or controversial. The Earth is flat.

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Re: Best way to heat basement?

Post by NavyIC3 » Mon Jan 14, 2019 11:16 am

bloom2708 wrote:
Mon Jan 14, 2019 10:23 am


1. Use the Ecobee to run the fan 50 minutes out of each hour. Keep air circulating.
I believe blowers use quite a bit of electricity. Somewhere in the 400 -500 watt amount. This is something that should be considered as far as cost.
Last edited by NavyIC3 on Mon Jan 14, 2019 11:53 am, edited 1 time in total.

bloom2708
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Re: Best way to heat basement?

Post by bloom2708 » Mon Jan 14, 2019 11:19 am

NavyIC3 wrote:
Mon Jan 14, 2019 11:16 am
bloom2708 wrote:
Mon Jan 14, 2019 10:23 am


1. Use the Ecobee to run the fan 50 minutes out of each hour. Keep air circulating.
I believe blowers use quite a bit electricity. Somewhere in the 400 -500 watt amount. This is something that should be considered as far as cost.
We have a newer variable stage furnace. The low speed fan uses very little electricity. Specifically designed to be run. This will vary based on the system. An older one speed fan would use more electricity.

The fan runs when you are heating and cooling. Running fan only mixes cool and warm air. Pulling warm air from the top level and mixing it with cooler basement air. It isn't magic, but if you heat/cool less because of the fan running, you should come out ahead.
"A Stoic believes they don’t control the world around them, only how they respond--and that they must always respond with courage, temperance, wisdom, and justice." --Daily Stoic

Dottie57
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Re: Best way to heat basement?

Post by Dottie57 » Mon Jan 14, 2019 11:50 am

My parents used a space heater which worked well. Only on when adults downstairs.

My brother and his wife heat their 3 se a son porch in winter with a permanent gas fireplace/stove. It is great.

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dratkinson
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Re: Best way to heat basement?

Post by dratkinson » Mon Jan 14, 2019 4:48 pm

Recall an episode of "Ask This Old House" that described a system of wireless vents that retrofitted to existing registers. Then thermostats placed throughout the house talked to vents and furnace to direct heat where needed.

Search: http://www.google.com/search?q=wireless+furnace+vent


If you want to keep heat in the basement, would think you would need to keep basement door closed. So an open basement door and pet/child gate might defeat your purpose.
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ColoradoRick
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Re: Best way to heat basement?

Post by ColoradoRick » Mon Jan 14, 2019 6:19 pm

OP-fortfun - I read quickly all of the posts and didn't see something that happened in a rental we owned, so I will mention it. Not being a HVAC expert, we bought a house and the basement was basically unusable from January till March. THERE WAS NO COLD AIR RETURN.
If you don't have any, you might buy 8" flexible duct and run 2 cold air returns. However you didn't mention, so that may not be the problem. Obviously same state as you.

suemarkp
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Re: Best way to heat basement?

Post by suemarkp » Mon Jan 14, 2019 10:47 pm

Ithrive wrote:
Mon Jan 14, 2019 2:54 am
Doubling insulation R value cuts the heat loss in half. If you have no insulation in the walls (let's say they are R1) and you put R16 in the walls, the heat lost through the walls will decrease by a factor of 4. Making that wall R32 will reduce the heat loss by a factor of 5 (only a 20% improvement with a cost doubling of the insulation). So you quickly get diminishing returns with insulation and get the biggest bang for the buck in walls that are missing insulation. Same with doors and windows, but it is difficult to make huge gains here. Note that window U value is just the reciprocal of R value (e.g. U = .25 is the same as R4).
What does this mean?? Does this mean insulation is pointless??
Others gave correct shorter answers, here's a longer one. When you calculate heat loss of a structure (an ACCA Manual J calculation is what you perform to determine the heat loss), you add up all the losses from walls, ceilings, floors, and air infiltration. In a wall, you have the insulated portion, and then parts that can't be insulated near as well -- windows, skylights, and doors. When deciding how much you want to insulate a wall or ceiling, you look at this spreadsheet of numbers. You can bring the walls and ceilings to near zero loss, but the heat escaping through windows and air infiltration is so huge that it doesn't matter. If the walls were R2, doors and windows were R4, it would make sense to increase the wall insulation significantly because it is less than the doors/windows and there is much more area of wall versus doors/windows. At some point though, you get diminishing returns in cost -vs- heat loss.

Where those diminishing returns occurs is building specific. There are also practical considerations -- your walls are only so thick so R15 is about all that will fit in a 2x4 wall. Ceilings can take a lot more, but I'm not convinced going above R30 makes much sense because going from R30 to R60 doubles the cost and is probably reducing your overall heat loss by less than 10% (because of the window, door, and air leak losses which are unaffected).

At R30 in the ceiling and R13 in the wall, I'd spend next on better insulated windows (including sliding glass doors), and then look at an air-to-air heat exchanger, and then possibly exterior doors. However, your building code may require more than R30 in the ceiling, so you don't have a choice.
Mark | Kent, WA

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fortfun
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Re: Best way to heat basement?

Post by fortfun » Mon Jan 14, 2019 10:54 pm

ColoradoRick wrote:
Mon Jan 14, 2019 6:19 pm
OP-fortfun - I read quickly all of the posts and didn't see something that happened in a rental we owned, so I will mention it. Not being a HVAC expert, we bought a house and the basement was basically unusable from January till March. THERE WAS NO COLD AIR RETURN.
If you don't have any, you might buy 8" flexible duct and run 2 cold air returns. However you didn't mention, so that may not be the problem. Obviously same state as you.
Thanks Rick. I've got a couple but they are close to the supply lines. I'm afraid they may be sucking up the hot air before it can heat the basement fully. I should have spent a little more time/money/energy and ran the return vents down to the floor rather than keep them in the ceiling, ughh....
The biggest problem, but it's a good problem, is all the passive solar that we get on the first and second floors. On sunny days, we don't even need to run the heater, but that doesn't help the basement...

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fortfun
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Re: Best way to heat basement?

Post by fortfun » Mon Jan 14, 2019 10:57 pm

bloom2708 wrote:
Mon Jan 14, 2019 10:23 am
A few things to consider:

1. Use the Ecobee to run the fan 50 minutes out of each hour. Keep air circulating.
2. Cold air sinks, warm air rises. Nothing we can do about that.
3. The sun shining during the day can keep the main floor and top floors at temperature. The furnace doesn't run. Cold air pools downstairs
4. Do temp averaging with the main floor and basement during the winter.
5. Disable the feature that detects motion in a room and then doesn't use that sensor until occupied.

We have an ecobee3. 2 story house with full basement. 1 sensor upstairs, 2 on main level and 1 in the basement.

In the winter I close all top level vents. Main level and basement vents are open. I use the 2 main level and basement sensors for determining the avg temp. If it is 71, 70 and basement is 68, that makes the average 70. Temp is set to 71 and the system will run. Run the fan 50 to 55 minutes of each hour and keep air moving.

I can keep the basement and main levels right but then the upstairs is 2-3 degrees warmer. Or I can keep the top and main levels right, but then the basement is 2-3 degrees colder. Just as good as it gets without a zoned or multi-furnace home.

In the summer, I close the basement vents and partially open all vents on the main level.All vents upstairs are fully open. I then use the upstairs an 1 main level sensor for temp averaging. Getting cold air upstairs is the problem. It wants to sink back down to the basement.

I've learned that I can only get it so good. We have bedrooms on all 3 levels, so I can't abandon the basement and just allow it to be 10 degrees colder.

Good luck tinkering with your ecboee settings and vents open/partially open/closed. It is a great little device. Add a pack of additional sensors of you have cold spots. Proper venting is important. If the basement doesn't have enough vents and cold air return options, it will be difficult to remedy without adding a new heat source. A mini-split is a good idea. We have considered putting one upstairs to help for cooling in the summers.
Good info. Thanks Bloom! I think I'm going to add a few more vents down there! The ecobee is pretty cool.

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fortfun
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Re: UPDATE-Best way to heat basement?

Post by fortfun » Fri Jan 18, 2019 10:22 pm

For those following this post, I just added a 12"x12" register directly on one of the main supply lines in the basement. This seems to have done the trick. The basement is currently the same temperature as the 2nd floor. Now for a little drywall repair and touch up paint. Thanks for the helpful suggestions everyone!

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