how do you work out the Kilowatts required to heat a house?

Answer 1

I just got a new heat pump and needed a 3 Ton unit. That's 36,000 British Thermal Units (BTU) capacity to heat and cool. So if I measured the amount of current drawn by my heat pump on a day when it has to run continuously, I'd know how many Kilowatts it takes to run the unit and provide 36,000 BTU to the house. It probably draws about 12 Amperes at 220 Volt AC. So that's 2640 watts or 2.640 Kilowatts.

Answer 2

There is a manual used to calculate the heat loss and heat gain by a residential house. It is called a "J" manual. This manual will give specific "R" values for head losses thru windows and doors, and walls plus infiltration factors. One would measure the walls, windows, doors, etc. and obtain a square footage of each. That square footage is then multiplied by the appropriate "R" factor and a BTU loss or gain is then tallied for the entire house.

Then one goes to the"J" manual again, and in there is a formula to size your heating or cooling system in terms of Total size in Kilowatts or in the case of gas furnace in BTU's per hour needed on the coldest day.

You can buy a "j" manual at any Heating Supply house or you can obtain the same from your local library if they have one on the shelf.

Answer 3

Well, there are too many variables to work it out with no more information than that. Much depends on the heater used. some are more efficient than others. also do you want to know just the KW for heat or with the blowers and such that are needed to distribute it too. The heater should tell you the KW per hour of use. Then you have to figure out how many hours out of a day it is on, which will vary depending on outside temp and how well the house is insulated and such. Electric heat is usually the most costly there is. Heat pumps are fairly efficient, especially ground source heat pumps.

Answer 4

You need a heat calculator which you should be able to get from a Plumbers Merchant. This calculator takes into account if you have single glazing or double, cavity walls or cavity, solid floors or wood, and the area of the room to be heated to about 70F. Once it tells you what Kw you need for a room, then you need to work out what size radiator you need for a room. You can get a list of radiator sizes and how much the output is on each size.

Answer 5

All the major radiator manufacturers have computerised heatloss programs (stelrad, myson,barlo, etc) that you might be able to obtain from them (possibly free or for a small charge) or if you send them your drawings and list of materials that your property is built from (solid concrete floor, etc) they will work it out for you for a small charge (or sometimes free if you use their rads)

Answer 6

need to know so many variables in the house not enough info