How to improve radiator efficiency

Consider the following ways to improve radiator efficiency.

Control the temperature

Modern domestic radiators have thermostatic radiator valves (TRVs), which allow you to set the temperature (snowflake to 5).  Older radiators or radiators in public areas e.g. office or hotel corridors, may not have controls so TRVs can be retrofitted.

TRVs work by sensing the air temperature around them, and regulating the flow of hot water entering the radiators to keep a set temperature in a room.  They can help you save money and energy, by allowing you to set lower temperatures, and to turn off the heating in rooms that aren’t used.  If room thermostats are present then TRVs are not needed.  But if you do have them, you should keep the TRVs on their highest possible settings.

One last point.  TRVs need a free flow of air to sense the temperature so keep them clear of curtains, furniture and lamps.

Bleed the radiators

If your radiator is cold at the top and toasty at the bottom it is probably full of air so needs bleeding.  When the radiator is off, insert a radiator key into the square valve at the top of the radiator.  Turn the key slowly anticlockwise, while holding a cloth underneath.  You will hear a hissing sound as air escapes.  When the water starts to spurt out close the valve.

Ideally radiators should be bled annually.  If you have to do it more often or the air releasing has an odour, it may be that the heating system is corroding so a plumber should be consulted.  If manually bleeding all your radiators seems like hard work, you could invest automatic self-bleeding valves, for instance Aladdin HV30 Self-Bleed Automatic Radiator Valves.

Fit radiator reflector panels

Reflector panels are an easy way to improve the energy efficiency of your radiators.  Radiators fitted to exterior walls can lose up to 70% of their heat through the bricks and mortar.  Insulating radiator panels reflect heat away from the wall and out into your home, improves radiator efficiency by 10-20%.  This would save an average three bedroom semi-detached house with 4.5m2 radiators £60 a year or 250kg CO2.

Reflector panels are fitted without removing radiators and are best fitted behind radiators on exterior walls.  You can buy purpose made reflectors from most DIY stores or make your own using aluminium foil and cardboard.

To make your own reflectors, wrap a sheet of tin foil around a sheet of pre-cut cardboard.  Fit with the shiny side facing out to reflect heat back into the radiator.

Ready-made reflectors, although they cost more, are probably more effective.  For instance check out SuperFOIL RadPack Energy Saving Heat Reflector Radiator Foil, that can be cut to size then stuck behind radiators using double-sided tape.  Alternatively check out panels from Radflek or from Heatkeeper Energy Saving Radiator Panels – 10 pack.


Fit a radiator booster device

The Radiator Booster MK2 is an energy-saving device which helps to heat rooms faster.  It is positioned behind standard domestic radiators, utilising miniature 12V electric fans to suck the heat up from the radiator and transfers it out into the room quicker than any conventional convection.  This reduces heat loss through the wall and as it heats the room quicker, it allows the heating system to switch off sooner saving energy.

Fit radiator shelves

The jury appears to be out on whether radiator shelves actually work.  Shelves fitted above a radiator are claimed to help deflect rising heat, thus making the radiators markedly more efficient at heating a room.  Shelves are particularly effective if fitted above radiators underneath windows, so that the bottom of the curtains just rests on the shelf.  This prevents warm air from being trapped and wasted between the curtain and the window.

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  1. Just to amplify on your analysis of radiator reflectors:
    (a) reflectors made from kitchen foil will soon become inefficient, as aluminium oxidates very quickly and then loses its reflective quality.
    (b)There are only two radiator reflectors approved for use in the Governments Carbon Emission Reduction target (CERT) Scheme administered by Ofgem – Radflek and Heatkeeper. Independent testing of Radflek for the CERT Scheme has shown that Radflek is 23% more efficient than Heatkeeper. All test data for Radflek is disclosed on its website unlike its competitors.

  2. Using tin-foil as a reflective insulation does not really work because the tin-foil will quickly oxidise and tarnish. Within a couple of months will be useless. Also, tin-foil is very difficult to work with as it is very fragile and is easily torn.

    That said, there are a number of lacquered foils available that will not tarnish. However, buyers should beware of over engineered, over priced products for what is in reality a very low-tech solution that will have very limited results. And, remember, that it is only worth fitting a radiator foil behind radiators on external walls.

    I found the best option to be Radflec Radiator Reflector (not to be confused with Radflek) as it seems to be the cheapest, best value solution. In reality, Radflec is really just a smaller, more malleable, roll of BBA certified Foiltec from YBS.

    The idea of positioning a shelf above the radiator is entirely valid, particularly if the radiator reflector is continued from the wall to the underside of the shelf.

    • I am trying airtec double insulated foil. Foil either side of a ‘bubble wrap’ material. just hung loose behind the rads off the fixing brackets. Any thoughts ?

      • I have been experimenting, and find that if I place an electric fan up against the radiator it heats my living room up in no time. The fan has 4 speeds, and I run it on setting no. 2.

    • Re shelves over radiators – are there any style of radiator that this won’t work with or with which it could be hazardous? I have the style of radiator where the heat comes alot out fo the top and you usually shouldn’t put things directly on top of them.
      S McMellahn

  3. I have a combi system installed and I have found the material used for emergency thermal blankets to be quite effective when making up reflective board. Thick corrugated board is ideal for this, as it has excellent insulating qualities.
    Another thing I have done, is to insulate all the piping in the heating system, particularly around the boiler itself. Doing this, has reduced the amount of ‘on’ time considerably, and I would certainly recommend this. Don’t skimp on quality. Buy the best materials you can, and it will reward you handsomely.

  4. If Radflec with a “c” or home made reflective boards were as cost efficient at reducing energy and reducing CO2 emissions as Radflek with a “k”, then energy companies would be flocking to use those methods to help satisfy their obligations under the Government’s Carbon Emission Reduction Target (CERT) Scheme administered by Ofgem. This is because energy companies have no access to public subsidies to fund the spending required and so they will only use the most cost efficient products. The fact is that neither Radflec with a “c” nor Foiltec has been approved for use as radiator reflectors in the CERT scheme. Radflek with a “k” is the most efficient radiator reflector approved by Ofgem for use in CERT and is the exclusive radiator reflector partner of British Gas (the energy company with the largest number of domestic customers in the UK and so with the largest CERT obligation) in relation to its CERT obligations.

  5. have made my own “radiator reflectors” using cardboard and tin foil,I have fastened them to the back of the radiator as opposed to on the wall(less fiddly) will this work or do I need to move them to wall ??

    • I’m afraid that tin foil is not the right material for radiator reflectors for the reasons given above – it will quickly oxidise and tarnish and this severely reduces its reflectivity. In any event, reflective membranes work best with an air gap on each side. Contact with the radiator will result in heat conducting through the membrane and then being radiated towards the wall. If the membrane is stuck to the wall, heat will conduct through the membrane and into the wall. Your best bet is using Radflek, the most efficient radiator reflector on the market and approved by Ofgem for the CERT scheme which is mounted in the middle of the air gap behind the radiator. See

      • Surely it is very simple to replace the tin foil when this happens?
        Not sure but i’m guessing this is more cost effective?
        How long are the radiators on for from November to say March-April?
        I will be trying the tin foil method anyway changing the tinfoil when needed and consider the costs and the benefits after winter is over.

      • I’m taking Michael Watson’s comments with a grain of salt because it looks very much like he works for the company he’s touting. Doesn’t make it a bad product of course, but he’s getting plenty of search ranking juice from this webpage by keeping on mentioning it!

        I agree with R – replacing aluminium foil regularly is cost effective because you need to remove a posher panel regularly to dust it anyway. Think about the amount of dust, spiders webs, fluff, etc. that accumulates behind most radiators! Your fancy, super-reflective radiator panel will be just as useless when it is covered in dust, so why not replace it with a new sheet of foil instead of having to clean the thing? Also, aluminium foil is recyclable, whereas the fancy panel will probably have to go to landfill at the end of its life. Just saying.

      • Just to reply to A nonny mouse’s comment, I’m more than happy to confirm that I am involved in Radflek. I’m actually the CEO, but that doesn’t detract from the logic of my postings. The material from which Radflek is made has a certified life of at least 60 years (i.e. Radflek will remain as reflective as it was when manufactured for at least 60 years). The reflectivity of kitchen foil degrades surprisingly fast. To make a comparison, our 6 radiator pack contains 2.16 m2 of Radflek and currently costs £15.99 plus £1.99 P & P – so £17.98 in total. Randomly searching online grocers shows Tesco Strong Kitchen foil at £1.49 (without taking account of any delivery cost) for 3 m2. A standard SAP assumption for Central Heating is that it is on for 34 weeks of the year. If you were to replace 2.16 m2 of kitchen foil three times a year (which one could argue is not often enough, given the speed with which it degrades) for 60 years, you would be using 388.8 m2 which, at today’s prices, would cost £193.10. That seems rather an expensive and time consuming alternative to giving the Radflek a quick dust!! As to your recycling point, Radflek is recyclable.

        If using kitchen foil was cost-effective, Ofgem would surely approve it’s use in the Carbon Emissions Reduction Targets scheme and the Energy Saving Trust would be recommending its use – neither of which is the case. Indeed The Energy Savings Trust actively promotes radiator reflectors, creating a category for them in its Recommended Product scheme (where Radflek is such a Recommended Product).

  6. Emergency thermal blankets are rather flammable in the main and give off toxic fumes if they conbust. Please check to see if yours are flame retardant.

  7. Great article! Some very useful information. Just wanted to let you know, the link to the radiator booster website is incorrect. It might also be worth mentioning Radfan in this section too, admittedly I do work at Radfan so may be bias but it is a much more efficient radiator fan than the Radiator Booster because it has more than one fan and blows the warm air into the middle of the room rather than to the side of the radiator. Don’t just take my word for it, take a look at our raving Amazon reviews:

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