Frequently asked questions

If you need help with a system fitted by Constant Hot Water, please get in touch with the team. We do not provide repairs for systems installed by other companies.

We install wet, or water based, underfloor heating and electric underfloor heating. Wet systems can be fitted in three main ways: in screed, as an overlay system over an existing suitable floor, or between timber floor joists. Which method is right depends on the property, the floor construction and the project. We work on new builds, extensions and renovations for homeowners, builders and trade customers.

Either. We can supply and install the complete system, or carry out an installation only job where the materials are provided. Let us know which suits your project.

It depends on the size of the area, the type of system, the floor build up and whether we are supplying the materials. We do not publish prices or estimates, because every project is quoted properly once we understand what is involved. Send us the details and we will come back to you.

Talk to us about the cover on your project. It is best explained against the specific system and scope of work rather than in general terms.

We are based in Hayes, next to Bromley, and work across Bromley, South East London and Kent. We also take on suitable projects elsewhere in London. If you are not sure whether we cover your area, just ask.

It depends on the space and how it is being built. Wet systems are the usual choice for whole rooms, extensions, renovations and new builds. They run off your boiler or heat pump and are efficient to run over large areas. Electric systems suit smaller areas, single rooms and some situations where build up height is very tight. Tell us about your project and we will talk you through the options.

These are the three main ways a wet system is fitted. In screed means the pipework is installed before screed or concrete is laid over it, which suits new floors, extensions and any floor being dug out and rebuilt. Overlay means a low profile panel system is installed over an existing suitable floor, with the final floor finish installed above it. Between joists means the system is installed between timber floor joists. The right method depends on the property, the floor construction and the project, so we look at each one before advising.

Overlay underfloor heating, sometimes called low profile overlay underfloor heating, is a wet system built from shallow panels laid over an existing suitable floor. The pipe sits in the panels and the final floor finish is installed above it. Because there is no deep screed, it adds much less height than an in screed system, so it is often chosen for renovations and for heating one or two rooms. Whether it suits your project depends on the existing floor, so it is a good thing to look at on a site visit.

In screed systems add the depth of the insulation and the screed, so they suit floors that are being built or dug out. Overlay systems add much less, between joists systems sit within the depth of the floor, and electric mats add very little. The exact height depends on the system chosen, so tell us the floor levels and door heights you are working with.

Many finishes can be used, including tiles, stone, engineered wood, vinyl and carpet with a suitable underlay. Some, such as thick carpet or solid wood, need more thought than tiles or stone. Check the guidance from the manufacturer of the finish you have chosen and tell us your plans early.

Wet systems connect to a manifold that feeds each circuit, and the controls are set up so that rooms or zones can be managed to suit how you use them. Electric systems use a thermostat for each heated area. We set up the controls and show you how to use them.

A wet system uses continuous loops of pipe laid over insulation and connected to a manifold with controls. The heat comes from your boiler or heat pump. The pipework is covered by screed or by the floor finish, depending on the system.

Electric systems, which use a heating mat or cable under the floor finish, suit bathrooms, single rooms and smaller areas where a wet system would be more than the space needs. For larger areas and whole houses a wet system is usually the better choice.

Yes. A single room such as a bathroom or kitchen can have its own system. For a whole floor or a whole house a wet system is normally planned as a set of circuits.

Often, yes. A low profile overlay system sits on top of the existing floor and only adds a small amount of height, so you can heat a room, or a whole floor, without excavating for a deep screed. Whether it is the right approach depends on your floors, door heights and what else is happening in the room. It is a good thing to look at on a site visit.

Often, yes. Pipework can be laid between the joists with insulation below and the floorboards refitted on top, or an overlay system can go over the boards. Which suits best depends on the floor construction, so it is worth a look on a site visit.

Often, yes, as long as the existing floor is suitable. That means it needs to be sound and level enough to take the panels. The overlay system is laid over it and your chosen floor finish then goes on top. We check the floor on a site visit and tell you if it needs any preparation first.

Between joists means the wet system is installed between the timber joists of a floor. It suits properties with timber floors where the boards can come up. Insulation goes in first so the heat is directed up into the room, the pipework is laid and pressure tested, and the floorboards are then refitted on top.

It depends on the floor and on how much needs to be lifted. Overlay systems generally involve less disruption than digging out for a screed. We will explain what to expect when we quote and plan the work around your builder if you have one.

Yes. Send us the plans and tell us the heat source, and we will plan the layout, zones and manifold positions to suit. It helps to include the floor construction and your programme.

Yes. An extension can have its own underfloor heating circuit. Whether it also links to other rooms depends on the heat source and the existing floors, so tell us what is planned.

Screed needs time to cure before floor finishes go on, and the time depends on the type and depth of the screed. Your builder or screeder will advise, and we plan the installation around it.

That varies with the size and type of system and how the project is running around us. We will give you a realistic idea when we quote, and we work to fit in with your programme, particularly on building sites.

We connect the manifold and controls, and systems are pressure tested before the floor goes back over the top. We will set the system up and show you how to use it. For anything specific about what is included at handover on your project, ask us.

Yes. Underfloor heating spreads warmth across the whole floor, so it can run at the lower water temperatures a heat pump works best at. We design and install the underfloor side of the system and work alongside your heat pump installer. Talk to us early, because the two need to be planned together.

We design and install the underfloor heating. The heat pump itself is installed by your heat pump installer, and we are happy to work alongside them so the two halves work together.

Yes. We work for homeowners planning a renovation, extension or new home, and for builders, developers and other trade customers.

Yes. A lot of our work comes through builders, developers and contractors. We can take on the underfloor heating package on extensions, refurbishments and new builds, work from your drawings, and fit in around your programme. See our builders and trade partners page.

Yes, we take on commercial underfloor heating installations alongside our domestic work. Tell us about the project and we will let you know if we are a good fit.

Yes. Send the enquiry form first, then once we have replied you can email plans or photographs to constanthotwaterbr2@gmail.com or send them on WhatsApp on 07379 411 870.