Heating load in Fremont
A home in Fremont has to be heated against a design temperature of −21.0 °C. That figure is measured, not modelled: it is the 1st percentile of daily minimum temperature over 15 years at Fremont Municipal Airport, 3 km away.
Design temperature
−21.0 °C
Heating degree days
2,740
Coldest month
Jan
Coldest night on record
−28.8 °C
Coldest station in range
−22.8 °C
How many kilowatts
Heating power needed at the design temperature, in kilowatts, for a detached house. Pick the row that matches the building.
| Construction | Detached | Semi-detached | Terraced | Top-floor flat | Mid-floor flat | Ground-floor flat |
|---|---|---|---|---|---|---|
| Uninsulated, single glazed | 26.4 kW | 23.2 kW | 20.6 kW | 22.6 kW | 11.0 kW | 13.5 kW |
| Unfilled cavity, early double glazing | 17.9 kW | 15.4 kW | 13.5 kW | 13.1 kW | 7.9 kW | 10.0 kW |
| Insulated to 1980s standards | 10.2 kW | 9.2 kW | 8.4 kW | 7.9 kW | 5.7 kW | 7.2 kW |
| Modern, roughly 1995-2010 | 6.3 kW | 5.7 kW | 5.3 kW | 5.1 kW | 3.8 kW | 4.6 kW |
| Current building regulations | 4.8 kW | 4.4 kW | 4.1 kW | 4.0 kW | 3.0 kW | 3.6 kW |
| Passive house | 2.8 kW | 2.6 kW | 2.3 kW | 2.2 kW | 1.5 kW | 2.0 kW |
Where the heat goes
For a 120 m2 detached house of this construction, at the design temperature.
| Element | W | Share |
|---|---|---|
| Walls | 3,368 | 33% |
| Roof | 984 | 10% |
| Ground floor | 664 | 7% |
| Windows | 1,919 | 19% |
| Thermal bridges | 564 | 6% |
| Ventilation and draughts | 2,718 | 27% |
| Heating load | 10,217 | 10.2 kW |
Calculate it for your own home
The climate half of this is measured. The building half is yours to supply.
Monthly mean temperature
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| °C | −4.3 | −3.1 | 4.7 | 10.7 | 17.1 | 23.2 | 25.0 | 23.3 | 19.1 | 11.3 | 4.4 | −2.5 |
Where these numbers come from
- Measured: the design temperature, the degree days and the monthly means. All of it from one station, Fremont Municipal Airport, over 15 complete years.
- Assumed: everything about the building. The U-values are typical published figures for each construction era, not a survey of your house. Two houses of the same age and size can differ by a factor of two.
- No credit is taken for sunshine or for the heat given off by people and appliances. That is the EN 12831 convention, because the design condition is a still, dark night.
- This is space heating only. Domestic hot water is a separate load.
- This is a calculation, not a survey. Before spending money, have the building assessed.