Northern Ireland · Northern Ireland · updated 9 August 2026
See when local sunshine is likely to cover an air conditioner, what a typical solar array can generate, and which energy schemes serve Derry. The forecast updates through the day. The long-term figures come from the European Commission's PVGIS dataset.
Long-term local picture
PVGIS models a south-facing system at 35 degrees with 14% system losses. It is a consistent way to compare towns, but your roof direction, shade and equipment will change the result.
Representative climate year
The PVGIS typical meteorological year has an average July daily high of 17.5°C, with 1 days reaching at least 25°C and 12 hours at or above 24°C across the representative year.
How to size the system
Local weather helps estimate running hours. It does not size an air conditioner. An installer still needs room area, glazing, orientation, insulation, occupancy and external-unit constraints before specifying equipment.
Current support
This is an energy-efficiency scheme rather than an AC or solar grant. Funding is subject to eligibility, technical assessment and availability. Applicants must receive written approval before starting any work.
Read the scheme guide →These are planning guides, not fixed local quotations. Roof access, cable runs, room load and equipment choice can move the installed price.
AC + Solar
Indicative from £5,900
Match daytime cooling with solar generation.
Heat Pump + Solar
Indicative from £7,400
One system for heating and cooling, supported by solar.
AC + Solar + Battery
Indicative from £9,800
Store spare daytime solar for evening cooling.
Portable AC + Solar
Future UK option
Renters and flats: cooling without the install.
Conservatory Cooling
Indicative from £3,600
Make a hot glass room usable in summer.
Home Office Cooling
Indicative from £4,200
Match working-hour cooling with daytime solar.
Weather comes from MET Norway and refreshes every six hours. Long-term solar and climate figures come from EC JRC PVGIS. Grant information links to the responsible public body. Read the assumptions, source dates and limitations before using these figures for a purchase decision.
Read the methodology and sources →Tell us about the rooms you want to cool and the roof you have. We will review the request and, where we have a suitable route, introduce you to installers who can assess the property and quote.
No obligation. Availability varies by area. Grants are confirmed by the relevant scheme or installer.
Live 7-day outlook
| Day | High | Cooling | Solar | Coverage | Grid cost |
|---|---|---|---|---|---|
| Sun 6 Sept | 20.1°C | 0.0 kWh | 9.4 kWh | 100% | £0.00 |
| Mon 7 Sept | 15.2°C | 0.0 kWh | 7.6 kWh | 100% | £0.00 |
| Tue 8 Sept | 14.9°C | 0.0 kWh | 15.9 kWh | 100% | £0.00 |
| Wed 9 Sept | 14.6°C | 0.0 kWh | 4.4 kWh | 100% | £0.00 |
| Thu 10 Sept | 16.7°C | 0.0 kWh | 6.9 kWh | 100% | £0.00 |
| Fri 11 Sept | 15.4°C | 0.0 kWh | 13.4 kWh | 100% | £0.00 |
| Sat 12 Sept | 15.7°C | 0.0 kWh | 4.0 kWh | 100% | £0.00 |
Approximation for one 0.9 kW air conditioner running when the forecast reaches 24°C, paired with a 3.5 kWp array. Solar output is modelled from sun position and cloud cover. Electricity is costed at 26.11p/kWh, the Ofgem average capped unit rate for July to September 2026. Forecast data from MET Norway ↗.