Heating load in Florence
A home in Florence has to be heated against a design temperature of −16.1 °C. That figure is measured, not modelled: it is the 1st percentile of daily minimum temperature over 30 years at Cincinnati/Northern Kentucky Intl Ap, 6 km away.
Design temperature
−16.1 °C
Heating degree days
2,099
Coldest month
Jan
Coldest night on record
−31.2 °C
Coldest station in range
−18.3 °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 | 23.3 kW | 20.4 kW | 18.1 kW | 19.9 kW | 9.7 kW | 11.9 kW |
| Unfilled cavity, early double glazing | 15.8 kW | 13.6 kW | 11.9 kW | 11.5 kW | 7.0 kW | 8.8 kW |
| Insulated to 1980s standards | 9.0 kW | 8.1 kW | 7.4 kW | 6.9 kW | 5.0 kW | 6.4 kW |
| Modern, roughly 1995-2010 | 5.5 kW | 5.0 kW | 4.7 kW | 4.5 kW | 3.4 kW | 4.1 kW |
| Current building regulations | 4.2 kW | 3.9 kW | 3.6 kW | 3.5 kW | 2.6 kW | 3.2 kW |
| Passive house | 2.5 kW | 2.3 kW | 2.1 kW | 2.0 kW | 1.3 kW | 1.8 kW |
Where the heat goes
For a 120 m2 detached house of this construction, at the design temperature.
| Element | W | Share |
|---|---|---|
| Walls | 2,966 | 33% |
| Roof | 866 | 10% |
| Ground floor | 585 | 7% |
| Windows | 1,689 | 19% |
| Thermal bridges | 496 | 6% |
| Ventilation and draughts | 2,393 | 27% |
| Heating load | 8,996 | 9.0 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 | −0.4 | 1.5 | 6.5 | 12.7 | 17.9 | 22.4 | 24.3 | 23.7 | 20.0 | 13.4 | 7.0 | 2.1 |
Where these numbers come from
- Measured: the design temperature, the degree days and the monthly means. All of it from one station, Cincinnati/Northern Kentucky Intl Ap, over 30 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.