House Heating
November 30, 2004 4:24 AM   Subscribe

Heating question. I have a new home. It has a forced air furnace. I generally keep the thermostat set at 69 degrees. My roommate keeps bumping it to 72. Will this make a dramatic increase in the cost of the heating bill?

Would an electric space heater be a good solution for him, since he claims to be cold. I'm upstairs, he is downstairs. My place is always hot. His solution was for me to open a window, which seems completely wasteful.
posted by benjh to Home & Garden (23 answers total)
Heat rises. Naturally, this is a factor in him being "cold".

I suggest you either offer to switch locations with him, or tell him that he can take a larger share of the heating bill if he wants it so warm.

Definitely wouldn't suggest an electric space heater. I've always found them to be unsafe.
posted by Saydur at 4:36 AM on November 30, 2004

An electric heater will generally not do your utility bills any good at all, never mind the environmentally damaging inefficiencies of such a solution. I don't suppose it will do any good to tell him to get a jumper, but that is the most practical solution.
posted by biffa at 4:38 AM on November 30, 2004

69-72! Good thing your roommate doesn't live with me. I'd keep it at 62 but my wife usually talks me into pushing it up to 65. How the hell can he be cold when it's 69 degrees F. in the house? Tell him to wear a sweater and slippers.
posted by octothorpe at 4:56 AM on November 30, 2004

funny how nobody is actually answering your question[/snark]

While I'm no expert, I would guess that the 3 degree difference won't do *much* to your heating bill, unless 72 happens to be the magical threshold that means your heater is on basically all of the time. Most houses have a threshold like that, but it's a different temp for each.

Also - if you have ceiling fans (many forced air homes do...) put them on their winter setting and turn them on. This will keep the warm air from collecting on your ceiling.
posted by jaded at 5:49 AM on November 30, 2004

What jaded said.

You COULD try raising the thermostat for a month (realizing there are factors that make an assessment of the extra cost just a guesstimate).

You will need to know what you are being charged for a kilowatt-hour of electricity. This cost will be determined by your rate. When you get a bill, divide the kWh by the monetary charge and you will get an exact idea.

If your roomate wants to live barefoot and in shirtsleeves in the winter, it would seem reasonable to ask for them to pay extra on the heating bill, imco.
posted by reflecked at 5:54 AM on November 30, 2004


"By turning your thermostat back 10 to 15 degrees for 8 hours, you can save about 5 to 15 percent a year on your heating bill -- a savings of as much as 1 percent for each degree if the setback period is eight hours long... The percentage of savings from setback is greater for buildings in milder climates than for those in more severe climates."
posted by jperkins at 6:27 AM on November 30, 2004

Theoretically the amount of heat required should be proportional to the temperature difference between inside and outside of the house. If it is 40 outside the heat required for 72 versus 69 should be (72-40)/(69-40) or about %110.
posted by caddis at 7:06 AM on November 30, 2004

Does it help to think about it in these admittedly simplistic terms: Let's say you're heating the house 30 degrees above the outside temperature. Another 3 degrees is a 10% increase in the "amount" of heating. It seems to me that the heating cost increase should be proportional to the increase in the amount of heating. This jives with the link provided by jperkins, since in a milder climate the difference between the outside and inside temperature is lower and therefore any increase in inside temperature corresponds to a greater amount of heating than in a colder climate.

I imagine there are other factors involved, including design of the heater, electricity use by the fan, etc. Anyone with an HVAC background care to comment or correct?
posted by mollweide at 7:07 AM on November 30, 2004

Uh, that is 110%. ( I really need to do a better job of proof reading.)
posted by caddis at 7:11 AM on November 30, 2004

Try closing your vents, opening his, and making sure there is plenty of airflow between the floors. This should at least reduce the disparity.
posted by bh at 7:15 AM on November 30, 2004

I guess preview doesn't work too well when someone is posting at the exact same time as you. If two people on the internet say it, it must really be true.
posted by mollweide at 7:17 AM on November 30, 2004

Response by poster: We do have ceiling fans in most rooms, with the exception of my living room. I didn't even think to reverse the fans (it's been a long time since I've lived in a forced air building, always had apartments with steam heat). I did close several of my vents, but some rattle and probably need the vent covers replaced with newer ones.

I will try the fans to see if that helps the situation, as well as ensuring all proper vents are open.
posted by benjh at 7:36 AM on November 30, 2004

There are also usually dampers on the ducts coming out of the furnace that can be used to change the heat distribution in your house.
posted by cardboard at 8:08 AM on November 30, 2004

When I lived in an apartment with forced air, my landlord's advice was to pick a temperature and leave it there -- it wasn't the heating that cost so much as it was the gearing up/shutting down of the generator. So the extra few degrees may not cost all that much, but the constant up-downing of the thermostat might. Pick a compromise temperature and stay there.

Also, to others: Our forced air thermostat temperature bore little relation to the actual temperature inside the house, especially room by room. We could set it at 80 degrees and it might warm up to 70 or so in the bedroom, but the living room would stil be too cold to type in, even with a sweater and heavy socks.
posted by occhiblu at 8:33 AM on November 30, 2004

Different people have different comfort thresholds with regard to temperature. It would be wrong IMO to force someone to suffer just because you are comfortable. Similarly, you shouldn't have to suffer from an excess of heat. Try to find a compromise solution that you can both live with, rather than enforcing a solution based upon some almost irrelevant number. Hopefully some of the specific advice in this thread will help you to achieve that.
posted by rushmc at 9:12 AM on November 30, 2004

Programmable thermostats. Available at little hardware stores and big box monstrosities. Easy to install, easy to use. Mine warms up just before wake-up in the morning, just before getting home from work, and all day on the weekend. Set to 62 F. during weekdays while I'm at work. Don't know how I ever lived without it.
posted by gimonca at 9:56 AM on November 30, 2004

Some other things to think about:

- What kind of floor coverings does he have? Bare wood and tile floors feel colder. Rugs tend to feel warmer.

- Do you have a humidifier? Forced hot air systems tend to be very dry and dry air tends to feel cooler. You'll generally feel more comfortable overall with the proper humidity.

- If closing certain ducts still doesn't help, consider installing duct fans, which can increase airflow in individual ducts. They require power so they're not drop-ins.
posted by tommasz at 10:12 AM on November 30, 2004

occhiblu that is only really the case if you have a boiler(and a grossly oversized boiler at that) For your standard forced air NG or electric furnace it's not really a factor.

Another thing to try is check to see if your furnace has a recirc mode. Most furnaces with two speed fans will allow you to always run the furnace fan on low to help combat top>hot basement>cold situations.
posted by Mitheral at 10:44 AM on November 30, 2004

Definitely wouldn't suggest an electric space heater. I've always found them to be unsafe.

don't know how economical these things are in terms of power consumption, but as a safer alternative to space heaters, my folks swear by these.
posted by juv3nal at 12:16 PM on November 30, 2004

Would he wear a hat? That's what I do, and I'm fine in my 65F and lower house. You lose a lot of body heat through your head.

Also, you might try rigging up a temporary barrier between upstairs and downstairs (a blanket "curtain" hanging in the stairwell, perhaps?) that would impede the flow of all his warm air rising up to you.
posted by stinkeye at 2:36 PM on November 30, 2004

This happens the opposite way where I live. I rent the upper floor, owner lives downstairs. Old house. She has her thermostat set to 21C, but up here it was falling as low as 12, and we haven't even had snow yet. Doesn't do any good to tell me to wear a jumper or a hat, because there are regulations for minimum heat in rental units, and I'd expect them to be met. The only solution we could arrive at were a couple electric oil-based radiators, which do seem inefficient and dangerous, and a hassle to be plugging and unplugging everytime I leave the house. But there's more control for heating specific areas.
posted by TimTypeZed at 3:29 PM on November 30, 2004

Going back to the original question... Depends on your definition of "dramatic." My guess is the difference will be under $50/mon. Of course, this will change with the outside temperature, as others have explained above.

No, you cannot force anyone to live in a colder apartment than they can tolerate. Suggesting a humidifier and a rug can help, but suggesting a hat and a thicker sweater is rude. Unless they are running around in shorts and a t-shirt, you cannot expect them to pay more of the heat bill just because your apartment is sucking up the heat.
posted by copperbleu at 8:10 PM on November 30, 2004

It has already been mentioned that thermostats are often not reliable. You should measure the temperatures in rooms of interest. Maybe your roommate is always hanging out in cold rooms, while you are always in hot ones?!!?

Theoretically the amount of heat required should be proportional to the temperature difference between inside and outside of the house. If it is 40 outside the heat required for 72 versus 69 should be (72-40)/(69-40) or about %110.

This is pretty good. It is important to add, however, that occupancy (human bodies, lights, computers, etc.) contribute a lot of heat to rooms in use.

If the average outside temperature for a given month is 50 and you set your thermostat to 68 you may never require heating at all. But at 72 it would require 4 x 30 = 120 heating degree days (amount of heating = 4, number of days = 30) to maintain the higher temperature. An infinite percentage increase, of course (since it is zero heating at 68).

If the monthly average was 20 you would require 30 x 30 = 900 heating degree days for 68, but 34 x 30 = 1020 heating degree days for 72. Which is a 13% increase.

Using 50 two paragraphs up is just a guess, of course. The quality of insulation and the occupancy will determine the outside temperature where you begin to require heating.
posted by Chuckles at 10:00 PM on November 30, 2004

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