Your BER now drives more than comfort — it decides green mortgage rates, resale value, whether you can rent it out, and which grants you qualify for. Tell us your home's age, how it's heated and what's been upgraded, and we'll estimate the likely band and show the single change that moves it most. It's an indication for the question the official register can't answer for an un-assessed home — not a substitute for the real thing.
Build era is the biggest single driver — it sets the fabric and the building regulations in force, which is why a 1970s house and a 2015 house start worlds apart before any upgrade.
The heating system swings the rating hard — a heat pump lifts a BER, while electric storage or panel heaters sink it, because the BER counts the primary energy behind the electricity, not just what the meter reads.
Insulation and glazing are where retrofit spending goes, and where a poor band is usually won back. Pick what's actually in place today.
Renewables fittedTreat this as roughly ±1 band — a real assessment measures things this can't.
These are broad planning figures on the BER's kWh/m²/yr scale, not a DEAP calculation. A real BER also weighs floor area, air-tightness, thermal bridging, orientation, the hot-water system, ventilation and the exact products fitted — which is why only an assessment gives the certified number.
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This estimate is a signpost; a certified BER is the map. You legally need a real BER cert to sell or rent a home, and lenders want one to give you a green mortgage rate (typically for a B3 or better, with the best rates at A). More importantly, a registered assessor produces the advisory report that tells you the cost-optimal order of upgrades for your house — which is what stops people spending thousands on the wrong thing. So the honest first step isn't a builder, it's the assessment: it's a modest one-off cost, and it turns guesses like the one above into a plan. Once you have it, the SEAI grants (attic/wall insulation, heat pump, solar PV) cover a big share of the work — our sibling grant checkers price each one.
SEAI — what a BER is and how to get one →A registered assessor gives you the real band and an advisory report on the cheapest way to improve it — the single most useful €150-ish you can spend before any retrofit.
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The band comes from a transparent starting figure by build era on the BER's own kWh/m²/yr scale, adjusted for your heating system, insulation, glazing and renewables — every figure is shown in “How we got this”. It is deliberately coarse: a real BER runs the full DEAP methodology on measurements this tool has no way to see (floor area, air-tightness, thermal bridging, orientation, ventilation, hot-water detail, the exact products). So this is a plausible indication — good to about a band either way, less reliable at the extremes and for unusual houses — never a certified rating. It exists because the SEAI's public BER register only lists homes that have already been assessed; if yours hasn't, this answers the “roughly where do I stand, and what should I fix” question the register can't. Band thresholds follow the official SEAI scale (A1 <25 up to G >450 kWh/m²/yr). Figures last reviewed July 2026 — confirm current grant and green-mortgage terms before relying on them.
A Building Energy Rating measures how much energy a home is calculated to use for heating, hot water, ventilation and lighting, expressed as kilowatt-hours per square metre per year (kWh/m²/yr) and shown as a band from A1 (best, under 25) down to G (worst, over 450). A is a very energy-efficient home; a typical older Irish house sits around D or E; the national average is roughly a C/D. The lower the number, the cheaper the home is to run and the more it's worth.
Not exactly — and anyone who promises a precise band from a few questions is overselling. The certified rating only comes from a registered assessor who surveys the house and runs it through the official DEAP software. What you can do, and what this tool does, is estimate the likely band from the things that matter most (age, heating, insulation, glazing), which is genuinely useful for deciding whether to get assessed and what to prioritise. Think of it as the difference between a weather forecast and stepping outside: helpful, honest, not the final word.
Because the BER counts primary energy, not just what your meter shows. Electricity carries a high primary-energy factor in the calculation (energy is lost generating and delivering it), so a home on electric storage or panel heaters scores badly even though the heaters are 100% efficient at the wall. A heat pump flips that: it delivers three to four units of heat per unit of electricity, so it lands as a very efficient system and can lift a home by a band or more. Oil and gas sit in between, with a modern condensing boiler beating an old non-condensing one.
It depends on where you're starting, which is exactly what the “biggest single move” box above estimates for your inputs. As a rule of thumb, for an older poorly-insulated house the fabric comes first — attic then wall insulation give the biggest, cheapest jump and also make everything else work better. Once a house is reasonably insulated, switching from a fossil boiler or (especially) electric heating to a heat pump is usually the next big lever, and solar PV adds a further step. A real assessor's advisory report ranks these for your specific house and budget.
Increasingly, yes. Most Irish lenders now offer green mortgage rates — a discount for homes at a strong BER (commonly B3 or better, with the keenest rates reserved for A-rated homes), on new mortgages and often on switches. On resale, a better BER is a genuine selling point: buyers factor in running costs, and a poor rating can drag both price and time-on-market. And you can't legally advertise a home for sale or rent without a valid BER cert in the first place.
Effectively yes — the SEAI heat pump grant requires the home to be heat-pump-ready, meaning it loses heat slowly enough (a Heat Loss Indicator at or near 2.0), which in practice means a reasonably insulated house. That's the main reason the honest sequence is fabric first: insulate to lift the BER and the heat-loss figure, then the heat pump both qualifies for its grant and actually runs cheaply. Our SEAI heat pump and insulation grant checkers cover the grant side.
Typically in the region of €150 for a standard house, though it varies by assessor and size, so it's worth getting a couple of quotes. The cert is valid for ten years (or until you make changes significant enough to warrant a new one). Given it's required to sell, rent or claim a green rate, and that its advisory report can save you from misspending on the wrong upgrade, it's usually the highest-value first step in the whole retrofit journey.