Calculating House Heat Loss from Utility Bills

Calculating House Heat Loss from Utility Bills

Here is a development calculation, riding a 3-month meter learning for a mounted condominium. You can use any interval (but a minimal of two weeks of iciness weather is substantial). You can read the meter yourself for the principles, appearance at your furnace funds or telephone your utility to locate out contained in the party that they have got got marvelous data. The ordinary gasoline utilization of substitute gasoline-fired obstacle of dwelling package deal contained in the condominium is estimated from gasoline utility info and subtracted from the entire for the interval in query, in order that the gasoline requirement for heating may maybe maybe additionally be isolated. (Oil furnaces are harder to length riding this formula, on the other hand it's far going to also be maybe riding oil fill-up sessions and the diversity of litres released.)

The intention is to locate a relationship some of the significant gasoline fed on and the heating degree days (HDD). A heating degree day is truly the diversity of ranges of heating required over the trail of 24 hours, when compared to a reference temperature of 18C. For example, if the customary daily exterior temperature is 10C, then the diversity of heating degree days for that day is 18C – 10C = 8 HDD. You can get the approximate HDD on your calculation interval from the Environment Canada webpage. Use the suggestions from the "Degree Days: Below 18C" row.

Once the relationship of the HDD and gasoline intake is mounted, then that you simply will calculate gasoline intake for the format temperature on your zone. This temperature is every so occasionally to hand from a mechanical contractor or your vicinity growth officers. It significantly is now no longer inevitably the excessive minimal temperature; it may maybe maybe additionally be estimated from the customary temperature over 24 hours on the coldest day of the iciness. To approximate the format temperature: pass to the historic weather info on your trader on the Environment Canada webpage; find the coldest January over the primary effective in basic words exceedingly thousands of years; then flip into responsive to out the bottom daily customary temperature in that month; and use that as the format temperature. Being a degree or two out will now no longer make a bigger distinction contained in the calculation.

The example no longer as much as uses a format temperature of -35C. At that temperature, the optimal HDD per day is the emblem of fifty three, that's the excellence among 18C and -35C. Calculating the length of the furnace substantial on the coldest day of the yr will mean that the furnace has the ability to preserve any envisioned vicinity temperature. You can find a furnaces overall performance score on its EnerGuide label or contained in the product documentation.


Total gasoline intake from December to March = 1,320 m3
Estimated intake for other gasoline obstacle of dwelling package deal (info from utility) = 306 m3
Therefore, gasoline intake at some stage contained in the interval for heating = 1,320 – 306 = 1,014 m3
Heating degree days for that interval (from Environment Canada info) = 2,840 HDD
Heating intake simply by degree day = 1,014 m3/ 2,840 HDD = 0.3570 m3/HDD
Heating intake at fifty three HDD/day = (fifty three HDD/day)(0.3570 m3/HDD) = 18.nine m3/day
Where gasoline has an calories content of 37.five MJ/m3, and the recent furnace has an overall performance of 72 per cent, then:
Heat loss at fifty three HDD/day = (18.nine m3/day) (37.five MJ/m3)(0.72) = 510 MJ/day or 21.3 MJ/h*
According to the calories content of electrical drive, 3.6 MJ/h = 1 kW, then 21.3 MJ/h = five.nine kW
This warm loss will require a furnace that produces an output of 5.nine kW or about 20,a hundred Btu/h (1 kW is range of three,412 Btu/h).
If we let the CAN/CSA F280 permissible oversizing of forty per cent, then the extremely furnace sizing will be (1.4)(20,a hundred Btu/h) = range of 28,a hundred Btu/h.
If you're calculating for an oil furnace, heating oil has an calories content of 38.2 MJ/litre.
* Note: This calculation is equivalent, furthermore the undeniable truth that a series of persons assume the general performance facet is contained in the unsuitable obstacle. It significantly is now no longer inevitably. We are calculating the condominium warm loss particularly having a look out on gasoline used and furnace overall performance. A extra functional furnace can have released extra warm to the condominium, and the warm loss would possibly be extra suitable.