The cheapest way to heat a home office in Ireland
Quick answer: Heat the room you work in, not the house, with a small heater on a thermostat. A 9 m² box room in an averagely insulated house needs about 630 W, so a 650 W heater such as the Warmlite 650W 5-Fin Mini Oil Radiator costs at most €0.25 an hour at the day rate of €0.38/kWh: €1.98 for an 8-hour working day flat out, or about €1.19 if the thermostat keeps it at full power 60% of the time. Remote Working Relief lets you claim 30% of your electricity and heating costs, apportioned by the days you work from home.
Working from home in an Irish winter usually means one cold box room and the choice between heating the whole house all day or heating just that room. Heating one room with a small electric heater is almost always cheaper. Below is what it costs per hour, per working day and per week at Irish electricity prices, how big a heater the room needs, and the tax relief you can claim back.
What a working day costs
All figures use the day rate of €0.38/kWh, since office hours fall in the day. The thermostat columns assume the heater runs at full power 60% of the time, the same assumption our running cost calculator uses; a well-insulated room needs less, a draughty one more.
| Heater | Power | Per hour | 8-hour day, flat out | 8-hour day on a thermostat (60%) | 5-day week on a thermostat |
|---|---|---|---|---|---|
| Purus 600W Electric Radiator (Bathroom Safe, IP24) Panel or wall heater | 600 W | €0.23 | €1.82 | €1.09 | €5.47 |
| Warmlite 650W 5-Fin Mini Oil Radiator Oil-filled radiator | 650 W | €0.25 | €1.98 | €1.19 | €5.93 |
| MYLEK 1KW Smart WiFi Slim Panel Heater Panel or wall heater | 1 kW | €0.38 | €3.04 | €1.82 | €9.12 |
| Dreo 1500W Ceramic Space Heater Fan or ceramic heater | 1.5 kW | €0.57 | €4.56 | €2.74 | €13.68 |
How the cost is worked out: rated power in kW × €0.38 per kWh × hours, cross-checked against SEAI energy price statistics, July 2026. Power figures are the manufacturers’ published ratings.
How big a heater does a home office need?
Watts per square metre of floor, depending on how well the house holds heat. Under each figure is the smallest heater in our guides that covers it and what it costs for an 8-hour day on a thermostat.
| Office | Draughty / older house (BER E–G) | Average (BER C–D) | Well insulated (BER A–B) |
|---|---|---|---|
| 6 m² | 600 W 600 W heater: €1.09/day | 420 W 600 W heater: €1.09/day | 270 W 600 W heater: €1.09/day |
| 9 m² | 900 W 1 kW heater: €1.82/day | 630 W 650 W heater: €1.19/day | 405 W 600 W heater: €1.09/day |
| 12 m² | 1200 W 1.5 kW heater: €2.74/day | 840 W 1 kW heater: €1.82/day | 540 W 600 W heater: €1.09/day |
Claim some of it back: Remote Working Relief
If you work from home, Revenue lets you attribute 30% of the cost of electricity, heating and broadband to remote working, apportioned by the number of days you worked from home in the year. Weekends, public holidays and annual leave do not count. If your employer pays you a remote working allowance, that is deducted first; you can claim the relief if your employer pays less than €3.20 a day. The relief is given at your highest rate of tax, so keep your electricity bills.
Four habits that cut the cost
- Close the door. A small heater only keeps up with a small space.
- Let the thermostat work. Warm the room before you sit down, then let the thermostat hold it instead of running flat out.
- Use a timer. Have it switch on half an hour before you start and off at lunch and at the end of the day.
- Heat yourself first. A low-wattage heater pointed at your desk does more for you than a big one heating the far corner.
Frequently asked questions
How much does it cost to heat a home office for a day?
A 650 W heater costs €0.25 an hour at €0.38/kWh, so an 8-hour working day costs at most €1.98, and about €1.19 if a thermostat keeps it at full power 60% of the time. A 2 kW heater left on flat out all day costs €6.08.
Can I claim tax relief on heating when working from home in Ireland?
Yes. Revenue's Remote Working Relief lets you attribute 30% of the cost of electricity, heating and broadband to remote working, apportioned by the number of days you worked from home in the year. Any remote working allowance your employer pays you is deducted first.
What size heater do I need for a home office?
Roughly 70 W per square metre in an averagely insulated house, 100 W in a draughty one and 45 W in a well-insulated one. A 9 m² box room needs about 405–900 W.
Is a fan heater or an oil radiator better for a home office?
For a full working day, an oil-filled radiator or a panel heater on a thermostat: it is quiet on video calls and gives steady heat. A fan heater warms the room fastest in the morning but makes noise, so it suits a short blast before you sit down.
PickIreland is reader-supported. When you buy through links on our site, we may earn an affiliate commission at no extra cost to you. Running costs on this page are calculated from manufacturer-published rated power and are indicative, not measured.