Question about heating/cooling costs

madmax

If you had a 1500 square foot house and it costs $100 a month to heat or cool would a 3000 sq ft house cost you twice as much if both were in the same climate and equally insulated?
madmax

amulford

Not necessarily. It depends on the layout of the house and how smart the design of the comfort systems are. If you have the foresight to use convection and circulation, you could quite probably heat the larger house for very close to the same costs.

For example, just using ceiling fans to circulate the air in the house would help to distribute the heat in the winter and cool air in the summer. Or, say you have a 2 story. In the winter you would concentrate the heating to the first floor, and conversely focus cooling to the second floor, and let convection do the rest.

One of the keys to this is spending the time to insulate well and close up draft points.

Also making use of higher efficeincy equipment would help tremendously. Replacing a standard boiler with an on demand circulation system could save you as much as 60%.

madmax

Awesome info, thanks! So its not all the actual area, more in the way its moved around, or so I take it.

Dennis Gardner

Years ago on the eastern slope, everyone burned wood for heat, but the clean air initiatives took care of this a few years back. Insulate well and use efficient HVAC units. If you are buying used, require previous utility bills.

You could always contract with a couple CSU coeds for the winter for body heat.......:D

shadowofnight

Dennis Gardner wrote: »

You could always contract with a couple CSU coeds for the winter for body heat.......:D

That aint cheap either

WilliamM2

madmax wrote: »

Awesome info, thanks! So its not all the actual area, more in the way its moved around, or so I take it.

Not really, if the smaller house was setup as efficiently as the larger house, the smaller house would still be cheaper to heat and cool.

amulford

Dennis Gardner wrote: »

Years ago on the eastern slope, everyone burned wood for heat, but the clean air initiatives took care of this a few years back. Insulate well and use efficient HVAC units. If you are buying used, require previous utility bills.

You could always contract with a couple CSU coeds for the winter for body heat.......:D

I'm thinking of going back to it...

tonyb

the coeds or the wood burning ?:D

mule

When I had a engineer spec the new system I put in my house a couple years ago the questions he asked were,

What direction does the house face?

How many windows and what is the surface area of the windows?

Tree cover?

Area of the house and height of the ceilings.

So it would seem the radient heat from the sun plays a very big part, maybe bigger than the size of the house.

I went with a hydronic radient heat system, the instalation is very expensive, even with me doing the majority of the work, but in the long run it will pay for itself because of the over all efficiency. The comfort level is nice not to mention the fact that you don't have to hear the air blowing through heat ducts and the reduced dust is nice as well.

obieone

Maybe if you told us WHAT you're thinking of doing, we'd have a better clue:
Are you putting a 2nd flr. on your current location? Are you buying a bigger used house?
Are you building a house?
A general rule for calculations is 600 ft/2 per ton of cooling-so you'll need 5 tons-recommend splitting that into 2 systems, that way, when 1 breaks down, your not dying during a heatwave
Also, need to know where your located?

sucks2beme

If it's a used house, have the realtor request a copy of the last year's bills.
Best way to know what you're getting into.

madmax

This is too complicated. I think I'll just go with the coed idea.

amulford

tonyb wrote: »

the coeds or the wood burning ?:D

Both. That way somebody can keep the fire burning all of the time...;)

McLoki

Our first house was 1000 sq ft and built in the 60's. Our current house is 2500sq ft and was new when we purchaesed it. (it was a spec house so built to code, but no additional insulation over standard was used)

Our cost to heat and cool the two houses was roughly the same.

Michael

obieone

madmax wrote: »

This is too complicated. I think I'll just go with the coed idea.

Ah, yes. The Homer Simpson fallback position:
"Son, if it's too hard, it's not worth doing":D

madmax

I also like the Simpsons way of cleaning... But really, I was just trying to figure out if there was a direct relationship between amount of area and energy used to hold the same temperature. After more thought I can see it matters how many walls (surface area), ventilation etc. Its all going to depend on the exact circumstances.
madmax

amulford

Correct...

McLoki

It comes down to

• insulation in the house (how easily it transferes heat and cold from inside to outside)
• How well sealed the house is. (actual air transfer from inside to outside - makes a huge difference. Walking around your house (basement and attic usually) and filling any holes you find (wires going down, pipes coming out, cracks where boards meet, etc.) will pay you back in spades. House wrap really helps alot with this as well. Worth putting in if you are residing a house or building a new one)
• Efficiency of the furnace and A/C. My old house had the original heat and a/c. (heater was maybe 60% efficient at best) my new house has a 95% efficient furnace.
• How well the attic is ventalated. (in my old house, the attic had very little ventalation. My house would actually get hotter after the sun went down from all the heat held in the attic.)
• Stuff in the house. An empty house will have a much harder time maintaining its temperature than a house with stuff in it. (just like an empy refrigerator is not as efficient as a full one.)
• Oh yea, the size of the house matters as well, but it is just another factor like those listed above - not the only factor you should look at.
• In our case, the layout of the house mattered alot as well. In our old house, if we opened all the windows, it may or may not get any cooler (just no decent airflow) in our new house, it will get to outside temp pretty quickly as most of the windows (front to back) are in line with each other.

I am sure there is more, but that is all I can think of for now...

Michael

mrbigbluelight

Think of all the surface areas of your house as giant radiators: walls, roof, basement floor.

They release heat in the winter, they collect heat in the summer.

The heat transfer from the basement floor is relatively minimal because it's in direct contact with the earth. Despite global warming (;)), the earth temperature stays relatively constant.

The roof is one giant heat sink. Stay away from dark colors. Black may look spiffy, but it soaks up heat like a sponge in the summer. Stay with light colors that tend to reflect heat.

The walls/windows are the other big heat source.
Go with thicker walls, packed with quality insulation.
If you insist on a lot of windows, make sure they're quality/expensive windows during construction, filled with inert gas.
Have the house wrapped with Tyvek/Pinkwrap.

You need to have air turn over in the house to keep from getting a "sick" house, so use an air intake that utilizes a thermal wheel.

I used to spend more on an 800 square foot shotgun house that I lived in
than I do now (1400 square foot).

If you take care of business during construction, and take care of all "radiators", you can build a 3000 square foot house that cost $100 a month to heat/cool.

disneyjoe7

House orientation to the outside, windows facing west in the south or facing north in the north. Have effect on the heating / cooling bills.

obieone

Bro, your question is like the person who post's the statement 'My sub sounds like crap'
And then DOESN'T list their rig.
Pick one:
A. an addition
B. existing house
c. new build
I want to help, but I need more INPUT

madmax

Thank heaven my sub doesn't sound like crap... So I have a two story house which I was wondering if I finish the upstairs exactly like the downstairs if it would cost twice the amount I currently pay for heating and cooling the one floor. Right now the ceiling of the first floor is insulated very well so I don't see much gain for the first floor even if the upstairs temp is more stabilized.
madmax

McLoki

Add into your costs running the fan on your thermostate in the ON position rather than Auto. In my 2 story (cape cod actually) there is a 10 degree difference between each floor unless I run the fan on "ON" all the time. (adds about 10-20 per month to my bill)

On the good side, with a little better furnace filter it does make for a decent whole house air filter. (although you have to change the 3 month filters every month)

I do not think it will add even close to doubleing your payment. At worst it would be 50-75%. I would guess closer to 40-50% or so...

Sami

I have a 3000sq.ft. house, and summer time electric bill is about $500 a month, give or take. Of course the houses in here are not well insulated (horrible actually) so it adds a considerable amount to the energy used.

As for your question, a larger area is more efficient to cool so all other things being equal you'd be looking at less money per sq.ft. I'd have to check that with my college buddies who majored in that field but that's my understanding of the issue. Except if you're running the cooling on two separate units of course...

disneyjoe7

madmax wrote: »

Thank heaven my sub doesn't sound like crap... So I have a two story house which I was wondering if I finish the upstairs exactly like the downstairs if it would cost twice the amount I currently pay for heating and cooling the one floor. Right now the ceiling of the first floor is insulated very well so I don't see much gain for the first floor even if the upstairs temp is more stabilized.
madmax

I don't know **** but I pay the bill....

I think a 2nd story added for the same house sq ft, 125% to 150%. Add big west looking windows 200% - to 400% well that's my $.02 But do it and tells us what it is.