Calculating House Heat Loss from Utility Bills
- Author John Carle
- Published December 4, 2011
- Word count 629
Here is a sample calculation, using a three-month meter reading for a typical house. You can use any period (but at least two weeks of winter weather is necessary). You can read the meter yourself for the information, look at your furnace bills or phone your utility to see if they have appropriate records. The natural gas usage of other gas-fired appliances in the house is estimated from gas utility data and subtracted from the total for the period in question, so that the gas requirement for heating can be isolated. (Oil furnaces are harder to size using this method, but it may be possible using oil fill-up intervals and the number of litres delivered.)
The goal is to find a relationship between the gas consumed and the heating degree days (HDD). A heating degree day is essentially the number of degrees of heating required over the course of 24 hours, compared to a reference temperature of 18°C. For example, if the average daily outside temperature is 10°C, then the number of heating degree days for that day is 18°C - 10°C = 8 HDD. You can get the approximate HDD for your calculation period from the Environment Canada website. Use the data from the "Degree Days: Below 18°C" row.
Once the relationship of the HDD and gas consumption is established, then you can calculate gas consumption for the design temperature in your area. This temperature is usually available from a mechanical contractor or your local building officials. It is not the extreme minimum temperature; it can be estimated from the average temperature over 24 hours on the coldest day of the winter. To approximate the design temperature: go to the historical weather data for your community on the Environment Canada website; find the coldest January over the last several years; then pick out the lowest daily average temperature in that month; and use that as the design temperature. Being a degree or two out will not make a huge difference in the calculation.
The example below uses a design temperature of -35°C. At that temperature, the maximum HDD per day is equal to 53, which is the difference between 18°C and -35°C. Calculating the size of the furnace necessary on the coldest day of the year will mean that the furnace has the capacity to handle any expected local temperature. You can find a furnace’s efficiency rating on its EnerGuide label or in the product documentation.
Example
Total gas consumption from December to March = 1,320 m3
Estimated consumption for other gas appliances (data from utility) = 306 m3
Therefore, gas consumption during the period for heating = 1,320 - 306 = 1,014 m3
Heating degree days for that period (from Environment Canada data) = 2,840 HDD
Heating consumption by degree day = 1,014 m3/ 2,840 HDD = 0.3570 m3/HDD
Heating consumption at 53 HDD/day = (53 HDD/day)(0.3570 m3/HDD) = 18.9 m3/day
Where gas has an energy content of 37.5 MJ/m3, and the existing furnace has an efficiency of 72 per cent, then:
Heat loss at 53 HDD/day = (18.9 m3/day) (37.5 MJ/m3)(0.72) = 510 MJ/day or 21.3 MJ/h*
According to the energy content of electricity, 3.6 MJ/h = 1 kW, then 21.3 MJ/h = 5.9 kW
This heat loss would require a furnace that produces an output of 5.9 kW or about 20,100 Btu/h (1 kW is approximately 3,412 Btu/h).
If we allow the CAN/CSA F280 permissible oversizing of 40 per cent, then the proper furnace sizing would be (1.4)(20,100 Btu/h) = approximately 28,100 Btu/h.
If you are calculating for an oil furnace, heating oil has an energy content of 38.2 MJ/litre.
- Note: This calculation is correct, although many people think the efficiency factor is in the wrong place. It is not. We are calculating the house heat loss based on fuel used and furnace efficiency. A more efficient furnace will have delivered more heat to the house, and the heat loss will be higher.
John Carle
RE/MAX Real Estate Edmonton
102 12650 151 Ave
Edmonton, AB T5X 0A1
John@Knock-Knock.ca
780-937-7534 / 780-701-9090
Article source: https://articlebiz.comRate article
Article comments
There are no posted comments.
Related articles
- Why I’m Obsessed with Antique Armoires as Statement Home Bars
- Ranch Revival: Statement Doors & Artisanal Elegance
- Embracing the Sensuous Chaos of Vintage Carved Doors
- Southern Style Charm: Decorating with Hand-Carved Antique Armoires
- Vintage Revival: Eclectic Coffee Tables & Earthy Furniture
- Pattern Mixing with Soul: Anchoring Your Space with the Tree of Life Carved Door
- Of Textures, Tranquility, and Time: The Vintage Lattice Carved Lotus Door
- The Benefits of Regular Janitorial Cleaning for North Shore Offices
- The Ultimate Guide to “Extras Carte Funciara” in Romania
- The Color Soirée, Carved Doors and Bespoke Design That Radiate Soul
- Why More Canadian Homes Are Using Tile in Living Rooms and Beyond
- Bohemian Rhapsody at Home: How to Decorate Like a Rock 'n' Roll Mogul
- How to deter pest birds from your home and garden
- Platinum Heat and Air: Your Local HVAC Heroes in Minnesota
- Kitchen Countertops: Sintered Stone, Quartz, Marble, Granite,Kompacplus
- Design Focus: Bold Pantry Doors & Dramatic Powder Room Entrances That Elevate the Everyday
- Artistic Bohemian Farmhouse: Where Creativity Meets Rustic Calm
- Rooted in Whimsy: Maximalist Wall Paneling with Hand-Carved Doors
- Rooted & Refined: A Home Where Two Histories Meet
- A Personalized Aesthetic: Where Antiques Tell the Story of Your Home
- Moody Vibes Only: Statement Pieces
- Where Soul Meets Space: Curating with Character
- The Sky's the Limit: Aerial Roof Inspection Pros and Cons
- Enhance Your Home’s Exterior with Custom Gates
- The Antique Indian Door as an Artist’s Muse
- Majestic Portals: Styling Indian Palace Doors for Soulful Spaces
- 5 Best Tools to Manage Your Business
- Elevate Your Entryway with a Statement Wall: Carved Wood Panels
- How to Use Airconditioning to Create a Pet-Friendly Home
- Rooted in Heritage: The Rich Ranch Aesthetic with Antique Doors and Rustic Soul