How to fix uneven heating / cooling in house?

[Carpediem]

We have a 3 year old single story 3BR/2BA house (~2200 sq ft) with the master BR on one side of the house and the other two BRs located on the opposite side of the house. There is a short hallway connecting BRs 2 and 3 with a shared bathroom in between. The HVAC thermostat is located in this hallway and all the HVAC mechanicals are located in a small closet in this hallway as well. Again, this is on the opposite side of the house from the master bedroom.

The problem is the master bedroom gets warm at night when running the A/C because the opposite side of the house is cooler so the thermostat doesn't kick in. What is the best solution for fixing this situation?

We've considered having the thermostat relocated to the other side of the house, just outside our bedroom door. But are there better/easier/more cost effective options? Would some of the new fancy thermostats offer some type of solution?

 

[GrayHare]

Close some/all cold air vents in the areas that are too cool.

 

[OldShooter]

Assuming hot air heat, there are booster fans that can be added in ducts.

A few years ago we upgraded to a high-efficiency furnace with a blower that runs at low speed continuously. This helped quite a bit with our sunroom, which tended towards being cold in the winter.

 

[Rianne]

We have a 3 year old single story 3BR/2BA house (~2200 sq ft) with the master BR on one side of the house and the other two BRs located on the opposite side of the house. There is a short hallway connecting BRs 2 and 3 with a shared bathroom in between. The HVAC thermostat is located in this hallway and all the HVAC mechanicals are located in a small closet in this hallway as well. Again, this is on the opposite side of the house from the master bedroom.

The problem is the master bedroom gets warm at night when running the A/C because the opposite side of the house is cooler so the thermostat doesn't kick in. What is the best solution for fixing this situation?

We've considered having the thermostat relocated to the other side of the house, just outside our bedroom door. But are there better/easier/more cost effective options? Would some of the new fancy thermostats offer some type of solution?

We have a similar layout in a ranch. Our HVAC guy said to keep the house fan running constantly 24/7. This evens the flow of air throughout the house. And close vents where it is cooler if no one is there. We prefer to keep the constant flow and the vents open as we use both sides of the house often. We did have our vent system cleaned out 6 months ago.

 

[Hermit]

I have kept the fan running continuously in my last two homes with great success. With the fan running, my last house was always even throughout both the upstairs and downstairs when many of the neighborhood homes had two heating/cooling systems. The only problem was that I had to change the filters much more frequently. I also didn't have any dust in the house.

With the house I am currently building, I plan to run the high efficiency furnace fan continuously during the cold months and use the wood stove for most of the heat, but there is no air conditioning so I will open the windows in the summer and deal with the dust. I am putting heat return ducts at the top of the cathedral ceiling upstairs and at the floor in the basement to pull in and mix the hot and cold air.

 

[Red Badger]

Assuming hot air heat, there are booster fans that can be added in ducts.

A few years ago we upgraded to a high-efficiency furnace with a blower that runs at low speed continuously. This helped quite a bit with our sunroom, which tended towards being cold in the winter.

Our new unit came with a thermostat that cycles the fan about 35% of the time irrespective of heat / A/C running. It helps distribute the air throughout the house. It's a pretty basic thermostat, can't imagine it being over ~$50.

 

[Cobra9777]

Our prior house was same size and layout with similar problem. We solved it by leaving the master bedroom door open and running the ceiling fan on high in the living space that separated the master from the hall where the thermostat was. We also left all interior doors open so air could freely move around the house. I would never leave the HVAC blower fan running all the time. In my experience, ceiling fans are great for keeping the air moving and thus uniform in temperature.

 

[samclem]

Running the fan is the approach that is most likely to work. As mentioned, there are thermostats that will run the fan intermittently (e.g every 20 minutes) if the heat/cool hasn't run in that time. This saves some energy vs running the fan continuously.
Other things to check.
-If you have a multi-stage AC or heat system, be sure you have a thermostat that takes advantage of it, and that it is set up properly. You want the AC or heat to operate at the lowest setting whenever possible so the fan will run a long time.
- you may need to adjust the dampers (hopefully you have some) or the registers if the heating/cooling itself is unbalanced. Get a good electronic thermometer and check the temps in the rooms after the heat or AC has run for awhile, see if temps are even. If you don't have dampers, you will have to use the airflow throttles on the registers. It is not unusual to have to tweak things at the start of the heating season and again when it is time to run the AC. This, however, will not help keep temps even throughout the house when the system isn't running.

 

[Happyras]

Replace your stat with an Ecobee that comes with one remote wireless sensor. Put demand for the remote bedroom set up for times you will be there. AND/OR put in zone dampers on the ducting to isolate flow to where you want it at times you need it. Some of the other posts are very good, but running the fan constantly may work well, but cost the most. You may need to do this even with the new stat remote sensor, but the Ecobee figures it out for you and will drive the temp to the priority sensor.

 

[Carpediem]

Replace your stat with an Ecobee that comes with one remote wireless sensor.

Thank you! That remote sensor is exactly what I was hoping for. I'll probably give this a try but until I do, I'll try running the furnace fan at night as well as the ceiling fan in the living area.

 

[samclem]

Replace your stat with an Ecobee that comes with one remote wireless sensor. Put demand for the remote bedroom set up for times you will be there. AND/OR put in zone dampers on the ducting to isolate flow to where you want it at times you need it. Some of the other posts are very good, but running the fan constantly may work well, but cost the most. You may need to do this even with the new stat remote sensor, but the Ecobee figures it out for you and will drive the temp to the priority sensor.

Zone dampers would be a good approach, but can be costly (esp if the ducting needs to be upgraded to allow sufficient flow through the coil/heat exchanger when some areas are throttled back) and are another thing to break.

The remote sensor/Ecobee combo can help get the temps correct >in the room(s) of interest<, but if the air temp throughout the house isn't evened out, the OP can wind up spending a lot of money for utility bills and also inviting possible moisture problems.

As it is now, during AC season the bedroom in use gets hot compared to the area where the thermostat is located (maybe that bedroom has greater heat gain, maybe the ducts don't deliver enough cool air there when the system is on, etc). If we do nothing else other than install the remote thermostat from the Ecobee in that bedroom, then the "problem" BR will be kept sufficiently cool during nighttime hours (assuming there's sufficient duct capacity to that room). But, the AC system will run more than it does now, AND the "cool" areas of the house will be even cooler. The OP will be paying for cool air (to those rooms) and getting no benefit from it. Also, a room that has no in-insulation (either wall or ceiling) condensation problems at 72 deg interior temps can develop problems if it is kept at 65 deg.

Running the blower fan takes a very small amount of electricity (typically about 20%) compared to the electricity needed to run the air conditioning compressor + blower fan. The blower fan is even more efficient if it is one of the newer variable speed/DC models. Running the fan (continuously or intermittently as some thrermostats allow) and getting the temps closer to even throughout the house lets you get full use of all the cool air you've already paid for before the AC comes on again. Same thing in the winter, too.

IMO, a remote sensor can be part of the answer, but makes the most sense in this case if it is paired with efforts to get the temperatures evened out.

 

[Hermit]

....
Running the blower fan takes a very small amount of electricity (typically about 20%) compared to the electricity needed to run the air conditioning compressor + blower fan. The blower fan is even more efficient if it is one of the newer variable speed/DC models. Running the fan (continuously or intermittently as some thrermostats allow) and getting the temps closer to even throughout the house lets you get full use of all the cool air you've already paid for before the AC comes on again. Same thing in the winter, too.

This is the way I understand it and I did do some research when I first started running the fan all the time. I never had a problem with the fans and, if anything, the cost of maintaining a comfortable temperature went down.

 

[Winemaker]

If you think of the cool/hot air as cool/hot water filling up a partitioned box it may be easier for you to find "equilibrium". If you have a 2 story unit, it is easier to cool the upstairs if you close the doors to each room. If you don't, the cool air will never "fill" up the room, it will all run out the door and flow to the 1st floor.

As GrayHare posted, by closing vents or cold air returns, you try to keep the resistance the same to each room, or "open" the duct run on the furthest duct. Do you have cold air returns on the top and bottom in each room? If not, they are somewhat easy to create, with a drywall saw and a new grate.

The use of in duct fans may end up creating other problems, but sometimes work.

 

[fritz]

Zone dampers would be a good approach, but can be costly (esp if the ducting needs to be upgraded to allow sufficient flow through the coil/heat exchanger when some areas are throttled back) and are another thing to break.

The remote sensor/Ecobee combo can help get the temps correct >in the room(s) of interest<, but if the air temp throughout the house isn't evened out, the OP can wind up spending a lot of money for utility bills and also inviting possible moisture problems.

As it is now, during AC season the bedroom in use gets hot compared to the area where the thermostat is located (maybe that bedroom has greater heat gain, maybe the ducts don't deliver enough cool air there when the system is on, etc). If we do nothing else other than install the remote thermostat from the Ecobee in that bedroom, then the "problem" BR will be kept sufficiently cool during nighttime hours (assuming there's sufficient duct capacity to that room). But, the AC system will run more than it does now, AND the "cool" areas of the house will be even cooler. The OP will be paying for cool air (to those rooms) and getting no benefit from it. Also, a room that has no in-insulation (either wall or ceiling) condensation problems at 72 deg interior temps can develop problems if it is kept at 65 deg.

Running the blower fan takes a very small amount of electricity (typically about 20%) compared to the electricity needed to run the air conditioning compressor + blower fan. The blower fan is even more efficient if it is one of the newer variable speed/DC models. Running the fan (continuously or intermittently as some thrermostats allow) and getting the temps closer to even throughout the house lets you get full use of all the cool air you've already paid for before the AC comes on again. Same thing in the winter, too.

IMO, a remote sensor can be part of the answer, but makes the most sense in this case if it is paired with efforts to get the temperatures evened out.

Depending on the complexities of your system - you might look into a programmable thermostat that also has a programmable fan for a low cost fix attempt. I've used these in the past in homes that have uneven heating and cooling (usually standard single stage heating and cooling). This type of t-stat allows you to program the fan to run continuously in any of the (4) setback/setup periods. I used to use White Rogers 1F90 t-stats. A quick search shows this one has the feature -

Buy White-Rodgers 1F97-1277 Programmable 1 Heat/1 Cool Thermostat | White-Rodgers 1F97-1277

https://www.ebay.com/itm/White-Rodg...350132&hash=item590768af5f:g:UJwAAOSwmuVafN6z

You can program one of the time periods to have the fan run continuously while you sleep, and automatic (on/off) in the other periods. This works especially well with multilevel homes. I also used to stage some for 75F (overnight), 76F, 77F early/mid-morning (ramp up) cooling settings when the cooling doesn't run as much (overnight), and when the humidity builds in the home (taking showers in the morning). FYI - running the fan continuously will tend to add back some of the moisture removed by the A/C process (drys the indoor coil off by the continuous fan/air movement over it).

It is normally cooler in the overnight hours and early morning (most areas) and it's more efficient to run the cooling during those times (and the system runs less frequently). This is why trouble areas of homes suffer from heating/cooling deficiencies. Ramping temperature also helps to pre-cool/dry out the home for the heavier heat load later in the day (A/C cools by not only lowering the temperature, but by removing the moisture - moisture removal takes longer). It is a fairly easy do it yourself replacement, or an HVAC technician should be able to install one for you at reasonable costs (shop around).

 

[Human]

+1 for a smart thermostat, closing doors, running the fan

Be careful closing too many vents. We live in a two story and almost fried our furnace by restricting the air flow too much during the heating season to keep the first floor warmer.

 

[samclem]

Be careful closing too many vents. We live in a two story and almost fried our furnace by restricting the air flow too much during the heating season to keep the first floor warmer.

True. Many homes have very little extra duct capacity, and shutting off even a few registers will result in too little airflow over the AC coil or through the heat exchanger. This can cause the furnace to run too hot and can cause the AC evap coil to ice up. Plus, the higher static pressures cause the blower fan to work harder, use more energy, and can shorten its life.

I am re-doing the HVAC system in a Cape Cod style house right now. For the reasons you mentioned, I put in enough duct capacity downstairs to allow the upstairs ducts to be closed off almost entirely in the winter. In the summer, they'll need to be opened up to get enough cooling up there, and I know the fan will need to run to keep the temperatures relatively constant in the house (no matter what, it will still be a little warmer upstairs unless I do something drastic). I think it will work well, though I'm sure I'll have to fine-tune things.

 

[fritz]

True. Many homes have very little extra duct capacity, and shutting off even a few registers will result in too little airflow over the AC coil or through the heat exchanger. This can cause the furnace to run too hot and can cause the AC evap coil to ice up. Plus, the higher static pressures cause the blower fan to work harder, use more energy, and can shorten its life.

I am re-doing the HVAC system in a Cape Cod style house right now. For the reasons you mentioned, I put in enough duct capacity downstairs to allow the upstairs ducts to be closed off almost entirely in the winter. In the summer, they'll need to be opened up to get enough cooling up there, and I know the fan will need to run to keep the temperatures relatively constant in the house (no matter what, it will still be a little warmer upstairs unless I do something drastic). I think it will work well, though I'm sure I'll have to fine-tune things.

Ductwork is the Achilles Heel of just about every residential HVAC system. Most are inadequate at best, and result in the "deficient" rooms everyone complains about. It has been my observation that home price does not matter when it comes to ductwork (although high end homes do get better off the shelf ductwork). It is essential to design the ductwork system to maintain your static pressure and airflow for overall comfort. Too much - things fail, the system is extremely noisy and no one is happy. Too little - things fail, the system is extremely noisy and no one is happy. I've always been amazed at how well (and how long) furnaces and A/Cs stand up to poorly designed ductwork.

On two story homes (worst for uneven temperatures), there are damper systems out there that range from elaborate zoning to two zones with (or without) barometric bypass. These have been in use for decades, and work well addressing overall comfort.

 

[Ronstar]

Like others, we close doors and keep the HVAC fan running 24/7.

 

[Hermit]

Ductwork is the Achilles Heal of just about every residential HVAC system. Most are inadequate at best, and result in the "deficient" rooms everyone complains about. It has been my observation that home price does not matter when it comes to ductwork (although high end homes do get better off the shelf ductwork). It is essential to design the ductwork system to maintain your static pressure and airflow for overall comfort. Too much - things fail, the system is extremely noisy and no one is happy . Too little - things fail, the system is extremely noisy and no one is happy. I've always been amazed at how well (and how long) furnaces and A/Cs stand up to poorly designed ductwork.

On two story homes (worst for uneven temperatures), there are damper systems out there that range from elaborate zoning to two zones with (or without) barometric bypass. These have been in use for decades, and work well addressing overall comfort.

When I asked HVAC people about Manual J and Manual D calculations (used for proper system sizing), I got a deer-in-the-headlight stare. I finally found someone who knew what he was doing to size the furnace and ducts in my new house, but it took a while and he is not cheap.

 

[harley]

DD's new (to her) townhouse was relatively miserable this winter, with parts of the house running 15 degrees cooler than other parts. We tried a number of things like closing vents and doors and such, but it didn't help much. The air just wasn't reaching the end of the runs at all. There are obvious huge leaks in the ductwork, you could feel the air just blowing out all around the unit. At our recommendation she got an energy audit, and the major thing they found was that none of the duct joints were sealed. They've recommended using Aeroseal, which is a gas that they run through the vents that forms a seal on the inside of the ductwork. I did some research on it, and it seems to have good reviews and results. She's going to give that a try. It's not cheap (~$1500), but being comfortable is worth it. And since they originally thought they were going to have to replace the windows ($15K), it seems pretty cheap.

She also has some insulation issues in the attic, but I think that can wait a while. It will be interesting to see how much of a difference the Aeroseal will make on it's own. I might be able to do some of the insulation part. I'll take her husband up there with me and teach him to do a few things. He could use a couple lessons in both home repair as well as saving money by DIY.

 

[Lakewood90712]

We have a 3 year old single story 3BR/2BA house (~2200 sq ft) with the master BR on one side of the house and the other two BRs located on the opposite side of the house. There is a short hallway connecting BRs 2 and 3 with a shared bathroom in between. The HVAC thermostat is located in this hallway and all the HVAC mechanicals are located in a small closet in this hallway as well. Again, this is on the opposite side of the house from the master bedroom.

The problem is the master bedroom gets warm at night when running the A/C because the opposite side of the house is cooler so the thermostat doesn't kick in. What is the best solution for fixing this situation?

We've considered having the thermostat relocated to the other side of the house, just outside our bedroom door. But are there better/easier/more cost effective options? Would some of the new fancy thermostats offer some type of solution?

Going to need some expensive zoning ( active airflow control dampers and control system) and splitting the return air into 2 locations ( very difficult and expensive if the interior equipment is in a hallway closet mechanical space) especially if on a slab. .

Vast majority of these have a single return air with the T-stat located nearby. The return air should to be near the " Load" ( where the undesired hot air in summer and cold air in winter is ) and that is NOT in the middle of the house. Just plain bass ackwards, but it's the easy and cheap way most HVAC is installed .

A truly well engineered system can cost about double of a typical HVAC installation.

Seen a lot of people with this situation , most just accept the lousy set up , rather than spending a lot of $$ to fix an inadequate design .

 

[skipro33]

Our new unit came with a thermostat that cycles the fan about 35% of the time irrespective of heat / A/C running. It helps distribute the air throughout the house. It's a pretty basic thermostat, can't imagine it being over ~$50.

Ditto. Stirs up the air in those rooms that would otherwise get stuffy from lack of use. However, for this to work, the spare rooms on that side of the house need their doors to remain open so the air coming in has some place to go.

With the fan running significantly more than the chiller or heater, the filter needs to be changed more frequently than otherwise.

I recently purchased a ductless heat pump for the master bedroom suite. Have not installed it yet, but I calculate it will save me on my electric use by not needing to heat/cool all the house when we don't need to. Here's a link to what I got;
https://www.amazon.com/gp/product/B01DVW6G06/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[Sarah in SC]

I put a couple of $100 window AC units in the bedrooms to do essentially the same as skipro, and it works like a champ. The rest of the house doesn’t need to be cooled at night, so we actually have reduced the electric bill over the past couple of years by doing this.
In colder months, we have window fans above the bedroom doors (set in the transom) that help regulate airflow even when doors are closed.

 

[target2019]

The problem is the master bedroom gets warm at night when running the A/C because the opposite side of the house is cooler so the thermostat doesn't kick in. What is the best solution for fixing this situation?

Our home has same problem (on 2nd floor), but worse since we have long hallway between master and other bedrooms, which opens to a 2-story cathedral ceiling.
Cooling was insufficient due to age of HVAC, ductwork, etc. Over time we've updated HVAC, added attic insulation, changed thermostats, etc.
The very first improvement I made to home was to add 4 ceiling fans. The one which has gotten most use is the master bedroom. The ceiling is vaulted, and simple addition of ceiling fan means air is circulated, and air is pushed down throughout the night.
The fan should have remote, and a reverse setting. Push air down in summer, lift air in winter.
You also need to get in attic to see if ductwork is joined, condition of insulation, and the attic fan is working.

 

[Scrapr]

DD's new (to her) townhouse was relatively miserable this winter, with parts of the house running 15 degrees cooler than other parts. We tried a number of things like closing vents and doors and such, but it didn't help much. The air just wasn't reaching the end of the runs at all. There are obvious huge leaks in the ductwork, you could feel the air just blowing out all around the unit. At our recommendation she got an energy audit, and the major thing they found was that none of the duct joints were sealed. They've recommended using Aeroseal, which is a gas that they run through the vents that forms a seal on the inside of the ductwork. I did some research on it, and it seems to have good reviews and results. She's going to give that a try. It's not cheap (~$1500), but being comfortable is worth it. And since they originally thought they were going to have to replace the windows ($15K), it seems pretty cheap.

She also has some insulation issues in the attic, but I think that can wait a while. It will be interesting to see how much of a difference the Aeroseal will make on it's own. I might be able to do some of the insulation part. I'll take her husband up there with me and teach him to do a few things. He could use a couple lessons in both home repair as well as saving money by DIY.

Wouldn't the easier solution to sealing the ducts be some mastic at the duct joints? I have heard of the gas but have not heard any reviews, Let us know how it does

We tested our vents in our old home. 50% leakage! No wonder I was in a hoodie all the time. We did an energy audit as well. Helped tremendously to improve comfort