Far Infrared Heating. It’s heating, Jim, but not as we know it! (but you may need more power, Scotty)
(above) 600W 'Glass' FIR panels mounted on the lounge ceiling. A RAIS 2:1 double sided integrated stove is also in use as a supplementary / alternative heat source)
ACC HAUS founder, Jeff Rhys-Jones, shares his 'experiences' in the conversion of his 1920s home from gas to Far Infrared heating...
It’s been a year since I completed the renovation work on our 1920s era home, part of which was a rather bold move to ditch the traditional gas central heating, and instead switch to a completely different type of heating, Far Infrared (FIR). It’s certainly been an interesting (in both a good and bad way!) project and so I thought I would share our experiences on this blog to help any other ‘conFIRts’.
Quite a few of the challenges experienced probably require their own blog but I thought I would kick things off with a err - ‘brief’ - summary of the pros and cons for those interested.
What is Far Infrared (FIR) heating?
Far Infrared comes in many forms these days – wall & ceiling panels, underfloor heating, and even domestic hot water (DHW) and ‘wet’ central heating systems. Whatever the form, they all use the same principle of generating FIR by passing electric current through a panel containing layers of carbon graphite polyimide, copper, nickel & nano silver to around 100c at which point long wave infra read / FIR is emitted. Unlike a traditional electric room heater, FIR is only absorbed by ‘matter’ and not air, so it does not rely on convection for heat transfer. The theory goes that as you are not heating air, but matter, far less energy is required to heat the same space than traditional electric heaters.
Is FIR really far better?
I can confirm that it’s true, FIR panels *do* emit a more natural heat sensation, the analogy used by many companies who sell FIR panels, is that of the sensation of feeling the sun on your face, on a cold winter morning, is a claim I can verify – though I’m afraid you can change back out of those Speedos – you won’t get a tan!
There are quite a few listed health benefits, mainly because without heat convection, there is less house dust in circulation, so people with asthmatic conditions, or simply just don’t like the drying out / ‘Bombay duck’ feeling of traditional central heating will find living in a FIR home far more comfortable. Our old central heating system somehow used to suck the life out of me like a Dementor from Harry Potter which would lead to constant ‘window open, window shut’ arguments with the wife every night.
We no longer have a gas boiler or any radiators, so because of that – there’s no requirement for gas boiler repairs, gas checks, pumps, valves, pipes, leaks and the pain of annual radiator ‘weeing’ as the wife used to call it. Being electric and with no moving parts, a FIR solution is essentially 'solid state' and therefore requires pretty much no servicing and panels can simply be swapped out by a home owner if they do break. So it’s certainly a far more resilient & ‘sold state’ type of solution. So there are certainly savings made on not having to service it.
Where To Put Them?
(above) 400w FIR panel on ceiling of upstairs hall. Always try to match panel 'shapes' to match the space you intend to heat - so in this case, a long thin panel was a better choice than a square one.
The best place to fix FIR panels is on the ceiling, so this means a huge amount of wall space in your house can be reclaimed that was previously taken by ugly looking radiators. FIR panels are an interior decorators dream. Perhaps you don’t want to put anything on the wall at all – and you can feel really good about having a pure white space to look at. Some do!
Being electric, together with smart home technology, you can create some highly customised, and efficient heating regimes. Heat rooms based on individual preferences, perhaps automatically turn down if movement is not detected for a number of days. It’s true that the £/KwH is more for electricity than gas, but with a wet central heating solution, you can’t simply ‘move’ a working radiator from one room to another. With FIR you can heat three rooms in rotation, using a fixed kWH budget – so a bit like getting a heater, heating a room for a bit, physically moving it to the next, and so on, until all rooms are up to temp. Once rooms hit the desired temp, they drop out of the loop, and thus 'shortening' it, so that the remaining rooms get more heat, until they in turn drop out, until all rooms come out of the loop and heating is off. So it's a loop rotation system that 'spread' heat around the house.
(Above) One small part of the 'JEFRSS' aka Jeff's Extraordinary FIR Rotational Sequencing System - a custom Loxone based program which 'moves' FIR heat around the house, depending on the time of day, internal room temperature and outside air temperature.
FIR heating is quite responsive, unlike underfloor heating which can take quite a while to get going, you can ‘boost’ a FIR room back up to comfort temperature in a very short time. Likewise, if a room was ever to get too warm with FIR, the panels can simply be turned off.
The panels are very nearly 100% efficient. With no heat loss though boiler, pipes and other heating paraphernalia such as pumps. It takes 600 watts to run a 600w FIR panel, and all of this energy is transferred to the room – so there is virtually no loss at all aside from minimal resistance in electric copper cabling.
Finally, they can be powered by the sun. It’s going to be a while until a household can viably generate its own gas, but you can use solar to generate your own electricity. On a sunny winters day, if you have a large sized PV system on the roof (we have a 4KW system), you’ll likely not have to pay anything for your heating at all.
FIR – The Considerations
Any technology which is powered by electricity is going to be more expensive to run on paper, than gas, simply because the cost / KwH of electricity is far higher than using gas. So the key factors to a successful FIR deployment are as follows:
Insulation, insulation and insulation!
As with any heating solution, the better insulated your house, then the better it will retain its heat, and therefore the less time it will need to be on. If your house has poor insulation then the W/meter cubed required to heat your home will be higher, and therefore so will your electricity bill. Just with anything electric, it will be considerably higher! So work our your w/ meter cubed first, that will help you estimate your worst case scenario electricity bills.
Panel type and placement
This is rather crucial. Panels should be placed as central to a room as possible, and remember that FIR cannot pass around corners, so any strange shaped rooms would be better suited to multiple smaller panels, rather than a large central one.
Thermostats / temperature sensors
They more you have the more you can manage and optimise. Because FIR heats matter and not air (which is what thermostats measure) you would typical set a thermostat a few degrees lower for FIR than for traditional central heating. So 19.5c rather than 21.5c. Using smart home management systems such as the Loxone system which we use and recommend, you can even feed multiple temperature sensors into a room control system, so take readings from different parts of a room and from this calculate an average.
Smart Home Management Plans
This is certainly a topic in its own right, but basically, if you are thinking about FIR you really should also consider deploying it with full smart home integration, monitoring and reporting in order to control running costs. For our project we used the powerfully and highly functional Loxone Smart Home solution. ACC are a fully qualified / certified Loxone Silver partner - so please contact us about any Loxone requirements!
Secondary / Alternative heat source
To take the ‘heat’ out of deep winter bills, I would recommend building an additional high power heat source that uses and alternative energy source from electricity, a wood burning stove with passive heat circulation to other rooms in the house is a great choice – and something we installed. It means in a power cut, we don’t freeze!
Wiring & fixing points
I would caution anyone trying to retrofit FIR room by room, rather than part of a full refurb. If you have one room which is not on your central heating, then fine, but doing the whole house – that’s a big job. If you are refurbishing anyway, as we were – then this is the time to think about it. Make sure you isolate your panels to their own ‘rings’ and carefully calculate the max potential load on each ring.
Temperature Sensor Placement
This needs to be carefully thought out. If your sensors are too close to your panels, the entire room will not get up to heat, but conversely, placing them too far from the panels, you may find your panels are on more than they need to be. Thankfully Loxone make a wireless light switch with built in temperature and humidity sensor, so this gives you the ability to move it around to get the best placement.
A biggie! If you are buying FIR panels, you need to check the voltage input on the transformers. It’s possible (like ours) that the units are CE marked and run at 230v. This is totally legal, however, for ceiling panels in particular – can cause major problems, because the typical UK voltage is 240v – your FIR panels will run over wattage. So they will give out more heat – which you might think is good – but not so. To prevent them overheating, FIR panels have a built in overheat cut off, and up on the ceiling where it’s warmest, a panel that is supposed to run at 230v and 600w, on 240v will likely run at around 640w. Doesn’t sound like a lot, but this will cause the panels to overheat, and switch off.
So your FIR panels (as ours were) were simply never getting a long enough burn and were constantly clicking off and on. The solution rather than replace all the panels, and likely have to re-do all the mounting points (lot of work) – was to purchase in a VO or ‘Voltage Optimiser’ which enabled me to down step the voltage in the house from 240v to 226.5v – so very nearly 230v. This was only possible because we have all the panels on their own dedicated power rings, so we simply moved the FIR rings over to the VO and the problem was solved. It’s not really what at VO is supposed to do, but it really saved our bacon.
Another biggie. If you are doing a retro fit, then prepare for your EPC rating to drop like a stone. You will be subjected to a type of EPC check called an ‘rdSAP’ (residential SAP) type of assessment. This type of EPC check has many assumptions, and also, there is no ‘category’ for your FIR panels, so the rdSAP assessor will simply put them in as ‘Electric Panel Heaters’ which will result in an awful rating.
To get around this, you need to embark on something called ‘Full SAP’ – something usually done for new builds only. However - thanks to a brainwave by Mark Hunt at MH Energy Consultants - if you change your primary heat source (as we did) plus you have full architect's drawings, so floor plans, elevations and importantly cross sections. So this is a much more accurate figure can be calculated by a Full SAP assessor. The difference is huge. After rdSAP – for our renovated home, they came back with a rating of E, and very nearly nearly F (awful). Full SAP, the house was upgraded all the way to C. After the rating was awarded, ominously the powers that be (presumably surprised that an electric powered house could obtain a C rating) demanded a full EPC audit. That came back... with 100% accuracy – so C it was – and I have a strong suspicion that we own the only 100% FIR heated 1920s era property with a C rating in the UK - and who knows, perhaps Europe too?! With feed in tariffs (FITs) kicking in from D and better, you can see getting the Full SAP was important. Even without FITs – your EPC figure will no doubt be printed on the estate agents details about your home if you ever decided to sell, so a bad rating might make the property less attractive. New regulations coming in to force in 2018 could also prove extremely troublesome (you will not be able to let the property for rent!) if your EPC ratings are below E.
Is FIR cheaper than gas central heating?
For us, I’m pretty sure, no. At the moment, gas is seriously cheap compared to electrics, and boilers are getting more and more efficient all the time. We were one of the last households to scrape in with a FIT before the end of the year (last few days of 2015) We will be generating and earning much better yields from our 4Kw array through the summer, and we’ve estimated this will offset over the additional amount spent during the winter. There is still quite a bit of optimising to do in the house, plus some internal & external insulation that can be added to older external walls, plus we will have a much larger log store to enable us to buy wood in bigger bulk during the summer when it’s cheaper.
So next year I’m hoping we will be running a much tighter (and warmer) ship. Realistically though I think we will be paying pretty much the same.
Energy Usage & PV With FIR
Take a look at some of the following charts.
Firstly, lets look at the total FIR use for the house, which is approx 100sq meters downstairs, and the same upstairs - so we need to heat approx 200sq meters:
So - this time of year (Early April), outside temperatures are ranging from 5c at night to a high of 14 day time. The house needs from 15kWh to 33kWh to heat it.
Next lets take a look at the power generated by the PV system over the same period - which is 4KW:
You can see that clearly, the 10th and the 12th of April were quite sunny days. This time of year, due to the angle of the sun, you're not going to get the full power out of your PV array, but 17.5kWh is not bad for April.
The next chart shows the amount of energy used by the FIR system, whilst the PV was working. It's not simply a case of subtracting PV from FIR, because these are per day figures, and it's possible that some PV power was generated when FIR panels were off. But in any case, it gives you a nice indication of how much FIR power was being used after the PV had been taken off:
So aside the 7th, we are around the 20kWh per day mark at this time of year. This still make some people wince, however remember that in addition to the PV energy we are using, we are at the same time getting a good generation tariff too - and this more or less than covers the cost of what's left to pay. Finally in the main summer months when FIR is not needed at all, we will also be exporting power into the grid so we'll get a little extra for that too.
So…. Is FIR for you?
As mentioned above like with most things in life there are benefits and considerations.
The main takeaway point is that a FIR solution is not something that should be done on a whim and should be properly planned, and done as part of a major house refurb as there is quite a bit of wiring to do. There are also quite a few ‘gotchas’ such as panel transformer voltage issues and placement so it’s definitely a project which has the potential to go horribly wrong.
It should also be done in combination with Solar generation and perhaps wind too. Yes it’s likely that in the coldest parts of the year, there is not going to be much sun to power your FIR, but in the Autumn & Spring you will find that plenty of days (like this week!) are sunny but chilly. So your heating for free during the day, good home insulation will keep much of that day time warmth in so you’ll just be needing room by room top ups throughout the night. Today is a very sunny but chilly day, and I can see from the house computer that we’re not using anything from the grid, the house is nicely warm, and there is not a leaky valve or noisy pump in use. Mission accomplished!
Quite often in life, the cheapest isn’t always the best. Lifestyle is important. Going FIR for us was less about creating the cheapest possible heating solution, (for that we might have decided to go underfloor heating which I have a passionate hatred of) but more about creating the best quality of heat. Yes that's right - heat has quality! I just really like the type of heat these FIR panels give out, and the simplicity and room segment control that FIR panels give you.
As the developed world tries to wean itself off fossil fuels, I do feel a little satisfaction that my home is not (directly anyway) heated by them. As mentioned above, on some days, it entirely heats itself for nothing.
The future of heating your home is electric – in my opinion, that’s a cold certainty.
The big question is how little can you get away with using, and are you able to generate and perhaps store, any of it yourself.