Planning water-based underfloor heating for a new home, extension or renovation? You do not need to choose pipe spacing before your first conversation with an installer. Start with the rooms you want to heat, the floors you want to keep and the information you already have about your home.
Use the six lists below to prepare for a quote. Copy them into your notes or print this page. Beside each item, write ready, to confirm or not applicable. Add who will confirm any missing information. You can use the checklist without an account or a HeatAlgo purchase.
This guide covers heating with water circulating through pipes beneath the floor. Electric heating mats are outside its scope. You gather and check the project inputs; your installer reviews the proposed design for your property and the selected system before installation.
1. Floor plans, measurements and fixed features
- A plan for every floor included in the work, with its date or revision.
- Room names, intended uses, dimensions and ceiling heights.
- At least one measured dimension on each plan so its scale can be checked. Note whether other dimensions come from drawings or site measurements.
- Doors, stairs, kitchen units and island, sanitary fittings, fireplaces and other fixed features marked on the plan.
- Walls, doorways or room layouts that may still change.
Mark the rooms where you want underfloor heating and any areas you want to leave untouched. Fixed features are points to discuss with the installer, not a universal rule for where pipes may go. If a drawing no longer matches the house, flag the difference.
2. Floor construction, insulation and available height
- Whether the floor is solid or suspended, if known.
- Existing floor layers and insulation material and thickness, supported by drawings, specifications or photos where available.
- What will be retained, removed or rebuilt, and any known damp or floor-condition concerns.
- Available height for the complete new floor, including the finish, at doors, stairs, thresholds and adjoining rooms.
- Who will check the existing floor and confirm the proposed build-up.
Do not choose a system by its advertised panel thickness alone. Ask for the full floor build-up and the resulting finished floor levels. A solution for a new slab may need a different approach in a renovation. What the layers of a building element and the insulation thickness mean in your documents is explained in the heating glossary for clients. Leave unknown layers marked to confirm.
3. Intended floor finishes and product specifications
- Your preferred finish in each room: tiles, timber, vinyl, carpet or another material.
- The manufacturer, exact product and thickness where already chosen.
- Underlay and fixing or adhesive specifications, where applicable.
- The supplier's confirmation of suitability for water-based underfloor heating, thermal resistance information and any temperature limits or installation conditions.
- Rooms where you are still choosing between finishes.
Share the product sheets before the heating design is finalised. Ask the installer to check the proposed covering and heating output together. How much output the covering takes away, and why timber or carpet deliver less than tiles, is explained in the guide on underfloor flow temperature. A label saying "suitable for underfloor heating" is still a reason to read that product's conditions.
4. Heating system and available heat-loss information
- The existing or proposed boiler or heat pump, with model and specifications if known.
- Rooms that will retain radiators or another form of heating.
- Any room-by-room heat load calculation, with the building details and assumptions used.
- Planned changes to insulation, windows, room use or ventilation.
- Who will check the heat needed in each room against what the proposed heated floor can deliver.
Room area alone does not describe heat demand. What goes into a heat load calculation and what the result depends on is explained in what a heat load calculation is. If you have no calculation, say so and ask who will provide it. Do not guess insulation values or select a water temperature just to fill an empty field.
5. Manifold locations, pipe routes and room controls
- Possible locations for the manifold, the unit that connects the pipe loops, with space for access and servicing.
- Possible routes between the manifold and each room, with doorways, changes of level and other obstacles marked.
- Rooms you would like to control separately and how you expect to use them.
- Possible thermostat locations and any known wiring constraints.
- Areas that must remain available for furniture or storage.
Treat these as suggestions until checked. Ask the installer to include the pipe runs to and from the manifold in the loop design and to confirm access, connections and controls. Why the run to and from the manifold counts towards loop length is shown in the guide on pipe spacing and loop length.
6. Quote, design responsibility, checks and handover
- Who prepares the heating calculations and layout, and who reviews them for the actual property and selected system?
- Which drawings, assumptions, pipe specifications, loop lengths and design settings will be documented?
- Does the quote include floor preparation, insulation, pipework, manifold, controls, heat-source connections and floor reinstatement? What is excluded?
- Who coordinates the heating installer, screed contractor and flooring installer, and how are changes priced and agreed?
- Who carries out and records the pressure test before the pipes are covered, following the selected system's instructions?
- Who handles commissioning, flow adjustments, controls checks and the initial heating procedure required for the floor construction?
- Will you receive the final layout, loop labels, test and commissioning records, operating instructions and relevant warranty information?
Keep the answers with the quote so you can compare the scope of different offers. Agree the checks before work starts: EN 1264-4 provides for a pressure test before the screed is laid. Ask your installer for the instructions applicable to your chosen system, rather than copying test settings from another product.
Prepare your plan in HeatAlgo
Once you have gathered the information, you can prepare a water-based underfloor heating project in HeatAlgo. You provide and check the inputs and review the layout. You can then buy the printable plan and PDF report to discuss with your installer, who should review the proposed design for your home and selected system before installation.
See how to prepare your plan and report