House feels cold when heat is on 77 degrees

southarn_com4ortDecember 28, 2012

Hello all,

I have a 2 story 4 bedroom home built in '72 (VA), vinyl siding. I have the heat set to 77 degrees, the temp on my thermostat reads 77 degrees and I purchased a cheap thermometer which reads the same thing upstairs and down however the house is still cool to the point my family walks around in sweaters. The master bedroom temp reads 74 degrees (wife really hates this). I have added insulation in the attic and new windows. The home is all electric. I'm not sure what could be causing the chill and I hate to turn the heat up to 79 degrees. Any advice is much appreciated. Thanks in advance.

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What is your relative humidity ? Electric heat is VERY dry.
Too low and it's cold. Too high and it's cold . What is your outside temp.?

    Bookmark   December 28, 2012 at 6:30PM
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Kalining thanks for responding. I'm not sure what the relative humidity is. My current outside temp is 43 degrees though.

    Bookmark   December 28, 2012 at 6:45PM
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Electric heat=gas heat=hydronic heat. When you raise the temperature of air, its relative humidity (expressed as a percentage) drops and so it becomes drier. When temperature drops for a given amount of air, relative humidity increases and so it becomes more "humid".

The fuel or equipment used to heat a house has no effect on relative humidity. To say "electric heat is dry" is wrong.

    Bookmark   December 28, 2012 at 11:11PM
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You say the thermostat is set to 77 degrees but the master bedroom is at 74 degrees. What is the temperature of the other rooms?

Do you have a forced hot air system? Is your furnace located in the attic? Do you have outside air infiltration from windows or doors? When you set the temperature at 77 degrees, how low does the temperature need to drop before the thermostat calls for heat?

    Bookmark   December 29, 2012 at 9:25AM
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Yes, I have forced hot air. I also have two units one for upstairs and one for downstairs. One air handler is in the attic the other is in a closet downstairs. Currently I have the heat set to 79 degrees because the family was a little chilly with it set to 77, the current outside temp is 42 degrees. The thermostat downstairs reads 79 and the room themometer in that room (family) reads 76 the living room themometer reads 78. The upstairs thermostat reads 79 the master bed (2 vents plus 1 in the bath) themometer reads 74 along with 2 other bedrooms (1 vent) but the back bedroom (1 vent) reads 70 degrees. All vents are open. Although the room themometers read 74/76 there is still a chill. Once the thermostat reaches 1 degree above its set temp it goes off and comes back on 1 degree below the set temp. The family is still wearing sweats suits to bed.

    Bookmark   December 29, 2012 at 9:50PM
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You probably have air leaks from floors, fireplace, or doors. My gas furnace is at 70, but I feel cold air from floors and I feel a slight breeze circulating inside house.

    Bookmark   December 29, 2012 at 10:09PM
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You seem to have a lot of air infiltration causing a wind chill effect. You have a 5 degree temperature variation between the bedrooms. You are probably getting cold air falling out of the vents supplied by the attic furnace.

    Bookmark   December 29, 2012 at 11:06PM
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If it were 79f in my house, I'd be running around in my skivvies I'd be so hot.

You've got to have drafts or air infiltrations from somewhere, like the windows and such.

    Bookmark   December 31, 2012 at 3:04PM
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I don't necessarily disagree with Mike about wind chill but from the attic furnace vents? Come on, I have an attic air handler with ceiling vents and my house is totally comfortable at 69.

With that outside temp, even with bad infiltration, it has to be humidity. A cold slab would make it feel cold on the first floor - do you have slab construction?

OP is this your first winter in the house? You do realize that in VA with pretty high rates and an all electric older house, that you might be near $1000 a month if you keep it at 79 degrees?

Strategy - seal air leaks. Start in the attic. Remove all blown insulation and foam and caulk everything you can see. Then mastic seal all your ductwork - starting in the attic. The largest single source of air infiltration is often the fireplace - try to figure out a safe way of doing that. Sealing leaks will increase your indoor humidity and reduce any wind chill effect. Buy a humidistat but either way you need to seal the house. Humidifiers everywhere will help but what a PITA.

Hey snidely - would you agree that a heat pump runs more than a gas furnace - maybe 4 times as much air? If there are leaky ducts in unconditioned space there will be more drying. So yes, the fuel used can make a difference in drying....

    Bookmark   January 1, 2013 at 4:59AM
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"The upstairs thermostat reads 79 the master bed (2 vents plus 1 in the bath) themometer reads 74 along with 2 other bedrooms (1 vent) but the back bedroom (1 vent) reads 70 degrees."

I carefully read the OP's post again. The title of the post is misleading. The house has a 9 degree temperature variation. The OP is pushing the thermostat higher in order to make everyone in the family comfortable.

The cold rooms have either a duct problem, a high amount of air leakage from windows or a combination of both. Drafty windows and doors can make it feel colder if you are sitting in the cross breeze.

    Bookmark   January 1, 2013 at 10:46AM
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David, I have no experience with heat pumps for heating but I understand that the lower temp rise requires longer run times. I agree, more flow through leaky ducts would cause more infiltration. But you'd have the same effect with a multistage gas/propane/oil/electric resistance/hydronic furnace running at low stage. Or, for that matter, a single stage furnace of any kind when the homeowner sets the fan to "On" for air flow/air filtering.

Think of someone who drives in heavy urban traffic during the work day, and then on open highway at moderate speed at night. You wouldn't say that they get better gas mileage at night because of the darkness.

    Bookmark   January 1, 2013 at 2:02PM
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Thank you all for the posts. This is my first winter in the home however not my families first. I will take on the advice and get into the attic to check out the ductwork. I had insulation blown in the attic during the summer and yes the foundation is on a slab. I agree, at 79 degrees in anyone elses home I would be running around with skivvies on and holding a sweat rag as well. The heat does not run constantly my highest bill so far has been $197. I don't have a fireplace. It has to be in the attic especially for the colder upstairs bedroom because I had the window replaced during the summer months and I did the smoke test on it and all went well. Thanks again. Happy New Year.

    Bookmark   January 1, 2013 at 4:27PM
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Is the thermostat accurate?

    Bookmark   January 1, 2013 at 5:05PM
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Brickeyee, yes, the thermostat appears to be accurate. I placed a thermometer in the same room with both thermostats (upstairs/downstairs) and the thermometer reads the same temp. This is the coolest 79 degrees i've ever felt though.

    Bookmark   January 1, 2013 at 8:21PM
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Snidely - it took me a little while on the traffic reference and I get your point. Even a low stage gas furnace runs less than a heat pump (in most situtations). Does anyone really leave their fan ON in the winter?

So while it isn't technically the fuel that is causing the drying, it still appears that way to the average person. I live in an area where heatpumps with ducts in unconditioned space is very common. There is also the pressure differentials in rooms that are greater with heatpumps in poorly designed systems that drives greater infiltration through the walls etc - leading to more drying. The fact is that air flow can cause drying and does in most houses. Particularly in my region. Airflow varies based on fuel and mechanism of delivery. Hence - hydronic does not dry because there is no airflow, gas furnace dries a little because there is a little airflow and heatpumps dry the most because there is the most airflow.

So the practical result is that fuel and mechanism of delivery do effect humidity even if it isn't for the reason that people think.

In a leaky Southern older home, this is significant.

    Bookmark   January 2, 2013 at 6:11AM
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There are numerous 'draft detectors' on the market you can use to search for air leaks.

Even incense sticks can to a pretty decent job.
Just watch the smoke.

I built one years ago (it uses a 12 V bulb filament as the sensor) and have yet to find anything that works as well.

Smoke pencils are rather common.

This post was edited by brickeyee on Wed, Jan 2, 13 at 14:54

    Bookmark   January 2, 2013 at 12:02PM
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David - Sorry, it was too abstract a comment, just trying to point out the result of picking the wrong thing for cause and effect.

Inside air comes from outside air, and you need a steady inflow for it to be healthy and not stale. Whether because of leaky ducts, or sucked in by clothes dryers and exhaust fans, or from construction gaps or open doors, or even from a ventilation system (for tight houses).

I can't find the reference now, but as an example, if you take 40 deg F air at 100% humidity (heavy fog) and warm it to 70 deg F, its relative humidity is under 50%. With colder or less humid air, even lower relative humidity results when it's warmed. Without supplemental humidification, wintertime indoor air becomes very dry, and the colder it is outside, the lower will be the relative humidity inside. It has nothing to do with the heating source or mechanism.

I lived for a few years in an area where ALL residential and much commercial heating was hot water radiators. Everyone complained about how much the radiator heat dried up indoor air.

    Bookmark   January 2, 2013 at 12:50PM
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I know this is an old post but I'm still having the same problem. My downstairs wall thermostat reads 79 degrees the outside temp is 38 degrees the thermometer i have sitting on the table in the same room with the thermostat reads 75 degrees and the humidity reads 33%. I'm sitting here wearing jeans a t-shirt and a sweat shirt and I still feel a chill. If I get a humidifier would that help the chill? I've gone through the house and sealed air leaks.

    Bookmark   March 24, 2013 at 1:40AM
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a blower door test will show you all
the leaks, as will a duct test show
you duct leakage.

without these tests you only seal
what you feel & often miss large leaks.
an example of large leaks would be
fireplace open to attic
and gap between wall & ceilling hidden
by ceiling moldings. one is big the other
is small but covers large areas. is a source for energy
raters who test both house & ducts for
leakage. you would want someone with
experience in existing homes.

best of luck.

    Bookmark   March 24, 2013 at 11:34AM
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Thanks Energy Rater. I will look into the blower door test.

    Bookmark   March 28, 2013 at 10:06PM
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You could be suffering from cold walls, windows and that cold floor. If the walls, windows and floor are several degrees below that of the air temperature, you will still lose your body heat due to radiant heat loss. Just the opposite of standing in front of a fire outside. Even though the air between you and the fire is quite cold, the fire's radiant heat warms your body. Get one of those cheap infrared thermometers and take surface temp readings of everything.

    Bookmark   March 30, 2013 at 5:05PM
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