Inspiration and advice for your building project
Will it be one of the usual suspects or perhaps another form of space heating? Our guide to choosing your emitters. Includes advice on radiators, underfloor heating, skirting heating, MVHR and more.
Your choice of emitter will dictate the way in which heat is distributed and thus, critically, how it is experienced. While the standard, and cheapest, option is to hang a couple of basic panel radiators in each room – fine for those on a tight budget or looking to sell on – not many people creating their dream home settle for the ‘standard solution’ when it comes to comfort.
The original self-build must-have, underfloor heating offers an effective, efficient heating medium that’s out of sight and makes no demands on wall space. It works by effectively turning the entire floor area into a radiator, via warm-water pipes or electric mats concealed within the floor structure. The resulting gentle heat (due to the floor’s large surface area, it only needs to be a couple of degrees warmer than room temperature) rises steadily upwards, and there are no cold spots or draughts, making for a very comfortable environment. To add to that, underfloor heating is the perfect partner to a heat pump, which is effective at producing the low temperature required.
The downside to underfloor heating is that it is not exactly instantaneous, taking one or two hours to heat the room up, where as a radiator might take 20 minutes; although conversely radiators also cool down faster. The solution is to leave underfloor heating on 24/7 in the ‘heating season’, which doesn’t sound very efficient, but as the system can be programmed to maintain a minimum temperature of 16°C, it need never start from cold. This can be enhanced by adding weather compensation, which uses a sensor to react to outdoor temperature changes. Because it’s on so much, underfloor heating is ideally suited to those who enjoy spending a lot of time at home.
Underfloor heating is compatible with homes old and new, and can be installed in any type of floor structure, with lots of configurations available — but the best setup is where the pipes are embedded within a concrete screed, which is pumped on and around the pipework once laid, offering a high thermal mass and efficient heat transfer. Pipes can also be installed beneath floating concrete floors on insulation or in boards, and below suspended timber floors, often on plates or insulation sitting across the joists. If you have an existing concrete floor, you may prefer to use slim electric mats, but as these are more expensive to run they are usually restricted to small areas such as bathrooms.
Laying the Screed: In a new solid floor, the pipes are laid across insulation in the floor, held in place by clips, griptrack or laying panels. The system is pressure tested before the screed is laid and left to dry for 30 days.
The Retrofit Option: Once, the only option slim enough for laying over an existing solid floor (without increasing floor height) was electric mats, but slim water-based systems are now available, such as Polypipe’s Overlay (just 18mm thick).
Laying the pipes is not difficult, but connecting the manifold to the boiler is a more skilled job, so it’s best to get help here. It’s also advisable to work with a manufacturer to produce the initial design – which must be done at the early stages of the project so that the floor structure and insulation levels can be designed accordingly – which can be free, to ensure optimum effectiveness.
Underfloor heating can technically be used under any type of floor cover, but it won’t work at its optimum efficiency with wooden flooring, and extra pipework will be needed for the same result you would get with stone, which has a high thermal mass, or ceramic tiles, which are excellent conductors of heat; carpet also doesn’t work as effectively, and you need to aim for a combined tog rating of carpet and underlay of no more than 1.5.
It’s key that solid wood flooring is acclimatised to avoid warping, with the room slowly brought up to temperature over a matter of days.
No longer should radiators be an imposition on the room, with cheap pressed steel the default option — new models in aluminium, which is lightweight and quick to heat up, can be sleek and minimalist or ornate and beautiful. For traditional homes, cast iron column radiators are the ideal choice, hanging on to warmth long after the heating is switched off.
The advantage of radiators is that they are quick to warm up and easy to control, particularly with the new breed of TRVs (thermostatic radiator valves), such as the remote-controlled eTRV from Chalmor, which uses dual temperature sensors.
The size of a radiator depends on the containing room’s size and function, the number of doors or windows and the house’s insulation levels, and is calculated in BTUs (British Thermal Units), a figure which will allow you to order radiators which will provide enough heat, but not too much. An engineer or plumber will work it out for you or you can use an online calculator (try theradiatorcompany.co.uk).
As a rule, radiators work best when placed on external walls under windows and worst opposite them, but in new builds the standards of energy efficiency and airtightness are so high that you can be more flexible.
(MORE: Choosing the Right Radiator)
Doing away with radiators and cheaper than underfloor heating, skirting heating has the external appearance of regular skirting boards but conceals pipework or electrical elements – and can even hide away TV cables etc., too – which distribute gentle, even heat at a low temperature with minimal air movement. Unlike underfloor heating, skirting heating can be turned on and off to suit as its responsiveness is more akin to radiators. For more information, visit thermaskirt.com.
Common in North America, warm air heating is highly controllable and can also be configured to cool homes in summer; systems may also incorporate air-source heat pumps. The main issue with this type of heating is that it creates air movement, which some people find uncomfortable. For more information, see johnsonandstarley.co.uk.
An increasing number of self-builders aim to create a home so well insulated and airtight that it doesn’t need central heating. Instead they install mechanical ventilation systems with heat recovery (MVHR) to distribute heat, which could be given off by a woodburning stove or even just from general appliances. These systems are known to maintain temperatures of at least 18°C even in winter.