Infrared to Assist Underfloor Heating

matelodave

Underfloor heatings works like a storage heater, insfoar as it takes a long time to get up to temperature and then a long time to cools down. If you turn it off over night or during the day and let the room get cold it could easily take several hours to recover so it's more suited to continuous heating to maintain the room temp rather than a quick heat-up in the evenings.

If we let our rooms get stone cold, it take can 24 hours for them to get up to temp as we have a low temperature heatpump with underfloor heating . Our heatpump has weather compemsation and the ability to reduce the flow temp by a couple of degrees overnight so it lake a lot less time to rewarm the room by a couple of degrees that it does by trying to heat it from cold. In fact it runs almost continuosly during the winter months but at a lower temperature overnight

You could try running it longer rather than expecting it to get the room up to temperature is a short time and turning it down a bit rather than off overnight or during the day.

The other thing to take into account with underfloor heating is the type of floor covering. Ceramic tiles are best, wood or laminate it OK but carpet and underlay have to be low tog otherwise you are effectively insulating the top of the floor.  Add a rug and you've increased the insulation. We have ceramic tiles in the kitchen, ute and bathroom, laminate in the hall and low tog carpet and low tog underlay in the lounge dining room and bedrooms.

The same with furniture. Stuff with legs is OK as it lets the heat rise whereas a ginormous sofa and armchairs will just mask the floor. Same in the bedroom and big double bed masking several square meters of flooring reduces the heat output from the floor into the room.

The heat output of a wet underfloor system is around 50-100w.m2 depending on the pipe size, spacing and flow temperature so you could do your own heat loss calculation.(see here https://www.tradingdepot.co.uk/info/plumbing/polypipe/underfloor-heating-heat-output-tables/)

nirish

@matelodave thanks for the extensive reply, our underfloor is only controlled by the room temp thermostat.  Varying floor temperature sounds great but we don't have that functionality.  

I run it most of the day to heat the room to 21deg and set the temp to 18deg at night.

However in the depths of winter the room never gets much above 18deg as it can't overcome the heat loss and it drops to 14-15deg at night so is always freezing in there in the morning.

The heat output calculations you provide are interesting, previously heat loss for the room was calculated by me and others to be anywhere between 2500W-3500W.  The underfloor best case is closer to 2000W but with both chipboard and ply above the screed it may be closer to 1500W.

So what I'm REALLY struggling with is what heating to use to supplement it with.  As mentioned I'm keen on the easy installation of Infrared and other advantages but the cost and unknown element makes me vary and most people suggest other avenues.

doodling

Hi,

Based on your estimate of the existing room heating (2kW) then any 2kW electric heater will double the heating in the room.

If the "depths of winter" are -5C (and the room reaches 18C with the existing 2kW input) then adding a 2kW heater will allow the room temperature to reach a balmy 41C - probably best to get a heater with a thermostat!

I would buy the cheapest 2kW convector heater I could find and stick it on a time switch.  If that works for you then by all means consider something fancier but I'd start off cheap to see how things go.

Kiran

A few things worth considering, firstly the source of the heat loss, you can rent a thermal imaging scanner to see if you can pinpoint the source or pay a company to come and do a thermographic survey. Secondly, heating the double height space sounds like it's straining the duty of your existing heating system. It may be worth installing a ceiling fan that you can use to push the heat back down in the colder months and pull the heat up in the warmer months. 

Have you considered a wood stove/multifuel stove for the coldest periods?

cymruchris

I can't say I know a lot about the options you've been discussing - but have had fitted a heat source air con unit - had you considered something like that? To give you warmth in Winter, and cold air in the peak of Summer? Is that an option worth looking at? Rather than just looking at heat alone?

thrope

I am not an expert, but the price for the originally linked electric heater seems complete crazy to me. I find oil filled electric radiator with a thermostat the best electric heating option as they can heat and maintain a space nicely, quiet etc. You can get a 2kW+ electric radiator for <£100. Easy to move around (many are on wheels so can tuck out of the way behind a sofa when not in use), and much much cheaper to buy than the infrared. Can also get slimline wall mounted models. I also agree with the warm/cold AC system, but there would be some fan noise from a wall mounted blower unit (and noise outdoors from the outdoor compressor unit).

BUFF

thrope said:

 I find oil filled electric radiator with a thermostat the best electric heating option as they can heat and maintain a space nicely, quiet etc. You can get a 2kW+ electric radiator for <£100. Easy to move around (many are on wheels so can tuck out of the way behind a sofa when not in use), and much much cheaper to buy than the infrared

You can get a 1kW quartz ir heater for £17 so 2x=2kW output for £34