Getting a heat pump installed is one of the most significant energy upgrades an Irish home can make. But the installation is only half the story. The electricity tariff you are on determines whether your heat pump delivers the savings you expected or quietly runs up a bill that surprises you at year end.
This guide is specifically for households that already have a heat pump, or are planning to get one, and want to make sure they are on the right electricity tariff to get the most from it.
Why Your Tariff Matters So Much With a Heat Pump
A heat pump replaces gas or oil with electricity. A typical three-bedroom Irish home running a heat pump will use between 8,000 and 14,000 kWh of electricity per year — compared to perhaps 3,000–4,500 kWh for a home without one.
At current Irish electricity unit rates, that volume of electricity represents a significant cost. A difference of just 3–4 cent per kWh in your unit rate translates to €240–€560 per year on that level of consumption. Getting the tariff right matters far more for a heat pump household than for an average electricity user.
Standard Rate vs Time-of-Use: Which Is Better for Heat Pumps?
The single most important tariff decision for a heat pump owner is whether to use a standard flat rate or a time-of-use (smart meter) tariff with cheaper overnight rates.
Standard flat rate means you pay the same unit rate at all hours. This is simpler, but you are paying full price for every kWh regardless of when the heat pump runs.
Time-of-use (night rate) means cheaper electricity overnight (typically 11pm–8am) and more expensive electricity at peak times (typically 5pm–7pm on weekdays). If your heat pump runs predominantly overnight — which is the case in well-optimised systems — this can produce substantial savings.
The key variable is how much of your heat pump's consumption falls in the overnight window. Modern heat pump systems with weather compensation controls and programmable heating schedules can be set to run the majority of their heating cycle overnight, storing heat in the thermal mass of the building or in a hot water buffer tank, then drawing on that stored heat during the day.
If your installer has configured your system this way, a night rate tariff is almost certainly cheaper for you.
How Much Can the Right Tariff Save?
For a heat pump household using 10,000 kWh per year, with 60% of consumption falling overnight:
- 6,000 kWh at night rate (assume 18c/kWh): €1,080
- 4,000 kWh at day rate (assume 35c/kWh): €1,400
- Total: €2,480
The same consumption on a flat rate of 28c/kWh:
- 10,000 kWh × 28c: €2,800
That is a saving of approximately €320 per year from the tariff choice alone — before accounting for any difference between the cheapest flat rate and the cheapest smart tariff on the market.
At higher consumption levels (larger homes, older buildings requiring more heat), the saving scales up proportionally.
Which Suppliers Offer the Best Tariffs for Heat Pump Owners?
Not all smart meter tariffs are the same, and the overnight rate varies significantly between suppliers. In 2026, the suppliers with dedicated or particularly relevant smart tariffs include:
- Energia — their Smart Home and EV tariffs both offer competitive night rates; heat pump households are explicitly part of their target customer profile
- Electric Ireland — smart tariff options with overnight rates for smart meter customers
- Bord Gáis Energy — time-of-use tariff available; worth including in any comparison
- SSE Airtricity — smart meter tariff options for eligible customers
The specific overnight and daytime rates change regularly. Use GoSwitch to compare all current smart tariffs and find the cheapest overnight rate for your usage level.
Do You Need a Smart Meter?
Yes — time-of-use tariffs require a smart meter. ESB Networks is rolling out smart meters to every home in Ireland free of charge. If your home does not have one yet, you can apply directly through ESB Networks. Given that a heat pump household has strong financial reasons to access night rates, getting a smart meter installed should be a priority if you do not already have one.
Heat pump installers should be raising this point with customers during commissioning. If yours did not, it is worth acting on now.
Other Tariff Factors for Heat Pump Households
Standing charge: Heat pump households tend to use electricity consistently year-round (space heating in winter, hot water throughout the year), so the standing charge is less significant as a percentage of total cost than it is for low-usage households. Focus primarily on the unit rate.
Annual usage estimate: When comparing tariffs on GoSwitch or any other tool, enter your actual estimated annual kWh including your heat pump. A standard estimate of 4,200 kWh will underestimate your usage and produce misleading rankings. If you are not sure of your total, check your ESB Networks account or ask your heat pump installer for an estimate based on your home size and insulation level.
SEAI grants: If you have not yet installed your heat pump, SEAI offers grants of up to €6,500 towards air-to-water heat pump installation. Combining the grant with the right ongoing tariff significantly improves the financial case. Our solar and home energy guides cover grant eligibility in detail.
The Bottom Line
If you have a heat pump and you are still on a standard flat rate tariff — especially one that has been running for more than 12 months without a review — you are almost certainly paying more than necessary. The combination of high annual electricity consumption and a significant overnight rate discount makes heat pump households one of the clearest beneficiaries of switching to a smart tariff.
Run a comparison now using your actual estimated annual kWh, and pay close attention to the overnight unit rate when evaluating smart tariff options.