Replacing an old gas boiler: new condensing boiler, hybrid or heat pump?

It depends on four things you can check: how well your home holds heat, whether your radiators can heat it with cooler water, what you pay for electricity compared with gas, and which incentives apply where you live. A heat pump alone costs the least to run in a reasonably insulated home whose radiators work well at lower temperatures. A hybrid, a smaller heat pump working with a condensing gas boiler, suits homes that need very hot water on the coldest days. A new condensing boiler is the smallest job, but in Italy it has had no tax break since 2025 and keeps you on gas prices. If yours still works and passes its checks, there is time to compare quotes.

How do the three options compare?

	New condensing boiler	Hybrid (heat pump plus condensing boiler)	Heat pump alone
Running cost	Gas price; less gas than an old non-condensing boiler	In between: heat pump in mild weather, boiler when very cold	Lowest when efficient; radiators and electricity price decide
Space, work and supply	Old boiler’s place, condensate drain, suitable flue; no meter change	Outdoor unit plus boiler; usually same radiators; sometimes more meter power	Outdoor unit, often a hot-water tank; maybe larger radiators; electrical work, often more meter power; gas contract can close
Durability and upkeep	One appliance; yearly servicing and legal checks	Two appliances to service	Outdoor compressor unit; servicing as the maker requires

The public bodies consulted publish no lifespans; compare warranty years in the quotes.

A heat pump is more efficient the cooler the water it sends to the radiators, so small radiators in a poorly insulated home make it run hot and lose much of its advantage. It also runs on electricity: most Italian homes have a contracted power of 3 kW and the meter cuts the supply above 3.3 kW, says ARERA, which puts each extra kW at about 26 euro a year, VAT included.

What would each one cost to run?

Your home needs the same heat whatever produces it: start from last year’s gas use, work out the heat delivered, then price it from each machine.

Assumption	Value	Source
Gas used last year	1,000 Smc (standard cubic metres)	Example value, change it to yours
Energy in 1 Smc	about 10.7 kWh	ARERA example, 0.038576 GJ per Smc
Gas price	1.20 euro per Smc	Example value; VAT in, fixed charges out
Electricity price	0.30 euro per kWh	Example value; VAT in, fixed charges out
Old boiler, seasonal efficiency	80%	Example value
New condensing boiler	90%	The class A minimum that ENEA uses
Heat pump SCOP	3	Example value; read yours on the maker’s technical data sheet

SCOP says how many units of heat a heat pump gives for each unit of electricity over a whole heating season.

Heat delivered: 1,000 × 10.7 × 0.80, about 8,560 kWh a year.
Old boiler: 1,000 Smc × 1.20, about 1,200 euro.
New condensing boiler: 8,560 ÷ (10.7 × 0.90), about 890 Smc, so about 1,070 euro.
Heat pump: 8,560 ÷ 3, about 2,850 kWh of electricity, so about 860 euro.

How much it moves. With a SCOP of 2.5 instead of 3 the heat pump costs about 1,030 euro, close to the new boiler. With electricity at 0.35 instead of 0.30 euro per kWh, about 1,000 euro. Break-even: with these prices the heat pump beats the new boiler whenever its SCOP is above about 2.4; at 0.35 euro per kWh, above about 2.8.

Purchase price, incentives and fixed charges are left out: going all-electric ends the gas fixed charges, extra meter power adds about 26 euro per kW a year. For your own price per kWh, see How to read your electricity bill.

When does an old boiler have to be replaced, and when not?

Age alone obliges nothing. In Italy Article 8 of DPR 74/2013 requires an energy efficiency check during maintenance of heating systems above 10 kW. Boilers whose combustion efficiency is below the Annex B limits and cannot be restored by maintenance “devono essere sostituiti entro 180 giorni solari” (must be replaced within 180 calendar days) from the check.

Outside that case replacing is your choice, and deciding before the boiler fails leaves time to check whether a hybrid or a heat pump fits.

What does EU law say about gas boilers?

Directive (EU) 2024/1275 on the energy performance of buildings, of 24 April 2024, says:

Article 17(15): “From 1 January 2025, Member States shall not provide any financial incentives for the installation of stand-alone boilers powered by fossil fuels”, except projects selected for investment before 2025 under some EU funds.
Recital 14: “It should still be possible to provide financial incentives for the installation of hybrid heating systems with a considerable share of renewable energy, such as the combination of a boiler with solar thermal or with a heat pump.”
Article 13(7): “Member States shall strive to replace stand-alone boilers powered by fossil fuels in existing buildings, in line with the national phase-out plans for fossil fuel boilers.”
Annex II: national building renovation plans describe policies for “the phasing out of fossil fuels in heating and cooling with a view to a complete phasing out of fossil fuel boilers by 2040”.

The text does not ban selling, buying or installing a gas boiler, nor oblige anyone to remove one that works; 2040 is a goal for national plans, not a date when boilers become illegal. Article 13(1) lets each country set requirements on the emissions or fuel of heat generators, so any ban would come from national law. Countries had to apply Article 17(15) by 1 January 2025 and most of the rest by 29 May 2026 (Article 35).

Which incentives apply in Italy in 2026?

Checked on 31 October 2026; incentives can change and the 2027 rules are under discussion.

Gas boiler on its own: no tax break. The Agenzia delle Entrate writes: “Non sono detraibili le spese per sostituire impianti di climatizzazione invernale con caldaie uniche alimentate a combustibili fossili” (the cost of replacing heating with a single fossil-fuel boiler is not deductible). Its home renovation page applies the same exclusion from 1 January 2025; ENEA marks condensing boilers paid since then “NON AGEVOLABILI”.
Heat pump or factory-built hybrid: ecobonus. For spending in 2025 and 2026 the deduction is 50% when the owner (or someone with a property right such as usufruct) pays for work on the home that is their main residence, and 36% in every other case, tenants included (Law 207/2024, art. 1, c. 55, with the rates changed by Law 199/2025). The maximum deduction is 30,000 euro per home, spread over ten yearly instalments (ENEA guides for hybrids and heat pumps, 23 September 2026). The hybrid must be a heat pump and condensing boiler designed by the maker to work together, the heat pump at most half the boiler’s power. A description of the work goes to ENEA within 90 days of completion.
2027. The law in force (Law 199/2025, art. 1, c. 22) sets 36% for owners working on their main home and 30% in every other case. On 28 October 2026 the government approved the 2027 budget bill; its press release calls the home renovation deductions “confermate” for 2027 without giving rates. The 2027 rates depend on the law Parliament passes and publishes in the Gazzetta Ufficiale.
Conto Termico 3.0 (grant). The GSE pays private households in homes only for the works of its Title III, including heat pumps, factory-built hybrids and “add on” heat pumps: up to 65% of caps based on the system’s output and SCOP. You apply on Portaltermico within 90 days of finishing, and admission depends on the budget still available. Up to 15,000 euro is paid in one instalment, larger amounts in yearly instalments. Check with the GSE before combining it with a deduction.

What about Germany and the United Kingdom?

Checked on 31 October 2026; rules and grants can change.

Germany. Under § 43 of the Gebäudemodernisierungsgesetz (Federal Law Gazette of 28 July 2026), a gas, oil or LPG heater installed in an existing building after 29 July 2026 must get at least 10% of its heat from biomethane, bio-oil, biogenic LPG or hydrogen from 2029, 15% from 2030, 30% from 2035 and 60% from 2040. A heat pump hybrid meets the rule if the heat pump is large enough. The KfW 458 grant pays 30% to 80% of up to 28,000 euro of eligible cost for the first dwelling in the building (a single-family house), a cap that drops by 750 euro every six months from 1 February 2027. You apply in the “Meine KfW” portal before work starts, with a supply contract made conditional on the grant. Owner-occupiers who replace a gas or biomass heater at least 20 years old, or a working oil, coal, gas floor-unit or night-storage heater, and have the old one properly removed, get a 16% bonus that drops 4 points every six months from 1 February 2027 and ends for applications from 1 August 2028.
United Kingdom. The Boiler Upgrade Scheme (England and Wales, owners) gives £7,500 towards an air source (air-to-water) or ground source heat pump and £2,500 towards an air-to-air one, and states: “You cannot get a grant for a hybrid heat pump system”. The installer applies. Government statistics put the median cost of air-to-water heat pump installations paid through the scheme, as reported by installers, in July to September 2026 at £12,826, VAT and grant value included.

What should you check in a “boiler in instalments” offer?

Before signing an offer paid monthly, sometimes on the energy bill:

Is it a loan? Then EU rules give you a standard form with the annual percentage rate (APR), the total cost of credit in one figure, to compare with the cash price.
Exit, maintenance and paperwork. Check whether the balance falls due at once if you move or change supplier, whether a paid maintenance contract is compulsory, and who files the ENEA or GSE forms.
Withdrawal. For consumer credit you can withdraw within 14 calendar days of signing without giving a reason, repaying what you borrowed plus interest and any non-refundable charges the lender has already paid.

What should you ask an installer?

A heat loss calculation, not a size copied from the old boiler.
The water temperature your radiators need on the coldest day, and the heat pump’s SCOP at that temperature.
Whether your meter power is enough, and where the outdoor unit can go (in a block of flats, check the building’s rules).
At least three written quotes with the same scope and warranty years.

This page explains how it works and what to ask; it is not financial advice or a design. Electrical work and paperwork are for a qualified installer or advisor.

Where to go next

Is a heat pump worth it compared with a gas boiler?: when it pays off.
How to read your electricity bill: what you really pay per kWh.
Heat pump: how it moves heat from outside air into the home.
Heat pump vs gas boiler calculator works out the yearly running cost, the break-even point and the payback time for your home.
Home energy incentives by country lists grants and tax breaks for heat pumps, solar and batteries.

Common questions

Is it still possible to deduct 50% for replacing a gas boiler?

Not for a gas boiler on its own. The Agenzia delle Entrate says these replacements have been excluded since 1 January 2025, condensing boilers included. In 2026 heat pumps and factory-built hybrids that pair a heat pump with a condensing boiler still get 50% when the owner (or someone with a property right such as usufruct) pays for work on the home that is their main residence, and 36% in every other case, tenants included.

Is a hybrid boiler worth it?

It can be when your radiators need hot water on the coldest days: the heat pump covers mild weather and the boiler takes over when it is very cold. You keep a gas contract and two machines to service. In Italy a factory-built hybrid still qualifies for the ecobonus in 2026; the UK Boiler Upgrade Scheme gives no grant for a hybrid.

Is a condensing boiler or a heat pump better?

It depends on your home and your prices. With the example values on this page a heat pump costs less to run than a new condensing boiler whenever its seasonal efficiency (SCOP) is above about 2.4. Old small radiators or expensive electricity can push the heat pump below that line.

How long does a boiler last?

The public bodies consulted for this page do not publish a lifespan, so it does not quote one; compare the warranty years in each quote. In Italy the boiler must be replaced within 180 days if the periodic efficiency check finds a combustion efficiency below the legal limit that maintenance cannot fix. Otherwise replacing it is your choice.

Topics: heating, gas boilers, heat pumps, hybrid heating, incentives, Italy