Faced with a gas boiler to replace, two alternatives compare on site: the air-to-water heat pump, whose heat comes out at €50 to €70/MWh, and connection to a district heating network, between €60 and €90/MWh. Connecting to a district network calls for €3,000 to €10,000 of initial investment and only arises where a branch already serves the street. The choice actually turns on the water regime of the existing emitters and on the electrical capacity available at the meter, two points surveyed on the visit before any proposal. A radiator network designed for high temperature closes the door on a heat pump for as long as the envelope is not upgraded or the emitters resized.
Moving off gas in 2026: the criteria that really matter on site
On site, replacing a gas boiler isn't just a matter of fitting a heat pump. You first secure the need, then check feasibility, before talking brand or model.
Building type: single-family home, small multi-unit, commercial
In a house, the challenge is often the envelope and the space for the outdoor unit. In small multi-unit buildings, think plant room, hydraulics, controls and metering. In commercial buildings, start from usage patterns and time schedules. A serious audit avoids oversizing.
Emitters and temperatures: radiators, underfloor heating, high temperature
Look at the actual water regime. Well-sized underfloor heating and radiators open the door to low temperatures. If the network demands higher heat, a high-temperature heat pump may work, but heating-curve tuning, balancing and sludge removal often gain you more than 5 kW would.
Site constraints: available electricity, outdoor space, nuisance, access to district heating
Check available power, the subscription, three-phase supply and load shedding. Outdoors, anticipate footprint, defrost, condensate drainage and noise. If a district heating network runs nearby, compare. The right job is one that runs without callbacks.
Heat pumps: which solutions for which needs (and when it's the best alternative to gas)
A heat pump often becomes a genuine alternative to gas when the home is already well insulated and heating can run at low temperature. The right choice mainly depends on the emitters, the climate and the available space. The air-to-water route runs from the site survey to the required output, then to picking the equipment.
Air/water heat pump: the most common choice in renovation
It connects to the existing network (radiators or underfloor heating). It's the simplest solution when replacing a gas boiler, provided you size the power output correctly and target moderate water temperatures to keep good performance, including at part load.
Ground-source heat pump: performance and borehole constraints
Ground source offers stable performance thanks to soil temperature. In return, it needs space or a borehole, a higher budget, and sometimes procedures (declaration, soil study). It's attractive when needs are strong and steady.
Hybrid heat pump: a transitional option when gas stays in the picture
The heat pump covers the base load, the boiler handles the gas backup during severe cold or when the radiators demand too much heat. It's useful for phased renovation, but the goal remains to reduce gas run time. To go further on this topic, here's a case study on replacing a gas boiler with a heat pump in renovation.
District heating: an alternative to gas that's often underrated
Connection: distance, available power output, road and substation works
Before replacing a gas boiler, start by checking for a nearby network. The useful distance between the building and the main pipe, the power still available, and the easements all shape the project. Connection often involves road works for the trench and the tie-in, followed by installing a substation in a plant room, with a heat exchanger, metering and controls.
Performance and restraint: energy mix, cost stability, service continuity
A network performs well when its mix includes renewable and recovered energy. You also gain visibility with more stable pricing than gas, since energy purchasing is pooled and contracted. Service continuity is a strong point, with centralised maintenance. A backup heat pump can complement it for specific uses or peak demand.
Favourable cases: co-ownerships, dense urban areas, high-demand buildings
Connection is often worthwhile in co-ownerships and in cities, when several homes share a production plant. It becomes very attractive for buildings with high heating and hot-water demand, which pay off the substation faster. Think audit, sizing, and space freed up in the plant room.
Heat pump vs district heating vs gas: costs, performance, maintenance
Investment and recurring costs: subscription, maintenance, wear parts
A heat pump requires a higher investment than a gas boiler, but has few fixed costs. Mainly budget for annual maintenance, and wear parts like fans, circulators or the electronic board. District heating reduces the investment on the home side, but adds a subscription and a variable share on the bill. Gas combines an often-modest installation cost, a gas contract, and mandatory boiler maintenance.
Consumption and comfort: COP/SCOP, controls, inertia, backup
The heat pump performs well when the home is well insulated. Its COP varies with outdoor temperature, and the SCOP gives the annual picture. District heating delivers stable heat with good inertia, and simple controls. Gas offers a fast temperature rise, but consumption depends heavily on the boiler's settings and condition. A backup should be planned depending on emitters and flow temperatures.
After-sales service and operation: parts availability, contracts, responsibilities
For a heat pump, after-sales service depends on the brand and the refrigeration technician. Aim for a clear contract, with response times and parts availability. With district heating, operation is managed by the operator, and your responsibilities are often limited to the substation and the emitters. With gas, you keep control but also the burden, inspections, maintenance and potential safety component replacements.
Deciding and selling the right scenario to the client: a simple method for 2026
Quick decision tree: 5 questions to steer toward a heat pump or district heating
Save time with 5 questions, then propose a single priority scenario.
- Is district heating available and connectable?
- Is the subscription and substation accepted?
- Are the emitters compatible with low temperature?
- Is there outdoor space and is noise OK for a heat pump?
- Is insulation planned, or just a straight replacement?
Points of vigilance to avoid disputes: sizing, hydraulics, acoustics
No guesswork on power output. Build on a heat-loss assessment. On the hydraulic side, secure flow rates, balancing, and decoupling if needed. For acoustics, anticipate placement and anti-vibration mounts.
Support schemes and compliance: MaPrimeRénov', CEE, RGE, energy audit depending on the case
Frame the support schemes from the quote stage. MaPrimeRénov' and the CEE certificates are often combinable, with an RGE-certified company. In deep renovation, an energy audit and support are generally required. Keep technical data sheets, references, and attestations.
