What is the Ecohabitation Energy Efficiency Rating?
The Energy Efficiency Rating generated by Ecohabitation is based on the average consumption of a building of the same type as the building being rated, i.e. with the same square footage and same number of occupants. This rating can estimate if the building you are considering purchasing uses less energy than the average for similar homes for the same comfort level, in which case its environmental footprint will be lower than average, as well as annual heating costs. The result is a single number that gives an estimate of the performance of that home.
For example, if the result is "23% savings", it means that your new home would cost 23% less than the average home in annual energy cost. Likewise, "15% additional cost" would mean that it would cost 15% more than the average home of the same category.
The data taken into account for the rating is as follows:
- The living area – the greater the heated space, the greater the heat loss through the building envelope, generally.
- The number of occupants – each occupant increases the overall consumption by requiring their share of hot water, energy for cooking, lighting, etc.
- The area – the local climate has a direct impact on the consumption for heating and cooling. A house in Baie-Comeau consumes much more for heating than the same home in Montreal.
- Year of construction – building codes are becoming more demanding over time, older homes usually consume more than new constructions. The rating shows a comparison between home of the same type but also of the same period (usually a period of about 25 years).
- Construction type – single family dwellings consume more than a single unit of the same square footage in a duplex or triplex because it has more surfaces exposed to the outside, including contact with the ground. Possible types are : house, duplex, triplex or condo (the latter resembling a house in a multi-residential complex) .
- Twinning – a detached house incurs heat loss on all sides of the building, while a semi-detached, or end-of-row house will not have heat loss on one of its faces. Similarly, a house in the middle of row does not incur losses on two of its faces. It is therefore crucial to take into account the pairing to compute any heat loss through the shell of a house.
However the following data are not taken into account:
- Basements or garages.
- The number of levels (e.g. a 2-storey building with 1,000 sq ft each will be considered a single floor building of 2000 sq. ft.)
- The presence of energy consuming features outside of the envelope such as a swimming pool or hot tub heated year round.
- Discontinuous occupation – a partially inhabited dwelling (e.g. a cottage) is considered to be inhabited at all times. Actual consumption therefore may give the impression of dealing with a highly efficient building.
The result of the calculation of the energy rating is only an estimate to give an objective albeit approximate judgment of the energy efficiency of a home. Energy costs of a home depend on many other factors that can not be taken into account in a precise manner here: behavioral habits of the occupants, the efficiency of electrical household appliances, including lighting, the type and efficiency of heat generating and cooling devices, the form of the building, the price of energy for the different sources used for the house, etc. A dwelling will thus vary its consumption simply by changing occupants. In addition, the rating is only an average for buildings of a given type. It is therefore not reasonable to expect that the consumption of future occupants will be consistent with the estimated consumption based on the consumption of previous occupants.
Ecohabitation is also not responsible for the validity of data entered by the real estate agent and supplied by the customer. Ecohabitation makes no warranty as to the accuracy of the energy rating and can not be held responsible for potential damages therefore to the use of this rating.