Far infra red heating

[Ramrod]

I'm building a single story 4x4m kitchen/diner extension off the back of my house. It will incorporate one of the back downstairs rooms that will have its back external wall removed so that the whole room is a continuous 8x4 space, about half of which will be glass walled (folding/sliding doors).

The builders quotes have come in rather high and I'm looking to shave off some of the cost.

I was hoping for wet underfloor heating but thats one of the few areas where I can make a considerable saving so I am looking at alternatives.

I have discounted electric underfloor heating as too expensive to run.
I could simply put another rad in the new room to augment the existing one but they take up space so I'd rather not.

By chance I came across infra red heating panels at a local showroom but they seem too good to be true, hence I'm asking you lot for your thoughts.

The panels can be disguised to look like a mirror or a picture, or simply part of the ceiling. Running costs are claimed to be about 3p/hr on average!
Link to how they work:http://www.glassheating.com/informat...ks-information
More blurb: http://www.lava-designs.com/en/das-produkt-lava-en/

My experience in life is that if something seems too good to be true then it generally is but I simply can't find a downside to this method of heating a room.
Anyone know any different?

[Rob]

At the end of the day, energy input = warmth. Whatever method you use, be it radiator, underfloor, infra red, your room will need a certain level of energy to keep it warm. So it's not about how much per hour, it might cost, but how many of those panels you might need for the space.

Your extension, compared to the rest of the house, being modern construction should be quite well insulated, reducing heat losses. Indeed it's quote possible that even wiht the extension, you don't need that much more heat input to keep the area warm, than for the existing room. But those folding doors, even double glazed could mess that up. Underfloor heating is only efficient if you have loads of insulation under the entire floor.

Personally I'd be sticking with a radiator, remember you don't have to have a horizontal one, there are plenty of attractive vertical designs. Even your infra red panel is going to use some wall space.

[Ramrod]

I'll just pop over to the supplier and ask how many panels I'd need for the space.
The extension will be very well insulated, in fact building control passed the plans first time round.
One of the reasons for the cost of the wet undrfloor install is that the back room would have to be excavated (concrete floor) to about 1ft depth in order to allow for the shedload of insulation.
I'd be looking to fit the panels to the ceiling.....

---------- Post added at 09:37 ---------- Previous post was at 08:57 ----------

Looks like I'd need panels that would cost about 12p/hr to run in a room that size......and they wouldn't need to be on all the time......purchase cost would be in the region of £500-£700, install cost negligable.
I have asked to be put in contact with existing customers/users to get their opinions.

[martyh]

Originally Posted by Ramrod

Looks like I'd need panels that would cost about 12p/hr to run in a room that size......and they wouldn't need to be on all the time......purchase cost would be in the region of £500-£700, install cost negligable.
I have asked to be put in contact with existing customers/users to get their opinions.

A wise move ,i am always doubtful of the price per hour claims ,those figures tend to be worked out under ideal conditions which are very rarely present in everyday locations .
Personally i would go with Robs suggestion and plumb another radiator into your existing system the cost will be much lower with very little extra running cost

[Taf]

Why not get a double rad to replace the one you already have?

[Ramrod]

Originally Posted by Taf

Why not get a double rad to replace the one you already have?

I'd like a nice warm stone floor & the rad atm is near one end of the room so it won't heat all the way to the other end. I could get an 'architectural' rad for the other end but it would take up space.

[Mick Fisher]

I can't remember what they are called but you used to be able to get long thin rads with fans in them for wall mounting just below ceiling height.

[Ramrod]

Originally Posted by Mick Fisher

I can't remember what they are called but you used to be able to get long thin rads with fans in them for wall mounting just below ceiling height.

I know what you mean.....too expensive to run....

[Mick Fisher]

Originally Posted by Ramrod

I know what you mean.....too expensive to run....

They were wet so about the same as a rad to run. IIRC very expensive to purchase though. Installation would be more than a standard rad due to the electrics required.

[Ramrod]

Ah, I was thinking of the electric ones.....

[qasdfdsaq]

The only number you should care about is efficiency, i.e. how many watts of heat does it produce for how many watts of gas/electric input.

[Ramrod]

Originally Posted by qasdfdsaq

The only number you should care about is efficiency, i.e. how many watts of heat does it produce for how many watts of gas/electric input.

Good question, don't know.
It's touted as being economical & eco-friendly........but then so is solar pv

[Rob]

There is no such thing as environmentally friendly, unless you are getting that heat source from a totally renewable source that doesn't combust, and even then there will be the resources used to create the heating appliance.

What we should be talking of is efficiency. In part that can relate to how the heat is distributed.

Radiators and other convectors will see warmer air rising. Fans might be used to push air around, however the overall effect is often cooler temperatures at the bottom of a room, just where everyone is lounging about. That is compounded if you have high ceilings.

Underfloor works by having an even heat spread around a room, at lowish temperatures and because your toes are warm, most people feel that is more comfortable. But it can take a while to get the system going, and will be unresponsive, as the structure of the floor has to first be heated before that heat spread into the room. Conversely that structure latent heat can help to create a balance. But if only one room in a house is heated this way, how easily that balance can be achieved is uncertain.

As the lined to diagrams show the infra red might seem better and more efficient, at least for some people, as the heat is reflected around a room, but that will also depend on where the panels are located. If the panels are high up, or ceiling mounted you might feel like your head is being cooked and yet that reflected heat hasn't got down to your feet?

[Ramrod]

Originally Posted by Rob

As the linked to diagrams show the infra red might seem better and more efficient, at least for some people, as the heat is reflected around a room, but that will also depend on where the panels are located. If the panels are high up, or ceiling mounted you might feel like your head is being cooked and yet that reflected heat hasn't got down to your feet?

Ceiling height won't be huge as we are building under permitted development rules.
One of the things I did get the salesman to admit to was that these panels work best on 'normal' height ceilings, rather than high ceilings......so thats a plus. I was wondering about the 'cooked head' thing myself.
They look perfect for the job otherwise.....I need input from people who have used these things so I'm hoping they contact me soon.

---------- Post added at 16:27 ---------- Previous post was at 16:17 ----------

From Wikipedia:

Far-infrared

This heating technology is used in some expensive infrared saunas. It is also found in space heaters. These heaters use use low watt density ceramic emitters (usually fairly big panels) which emit long wave infrared radiation. Because the heating elements are at a relatively low temperature, far-infrared heaters do not give emissions and smell from dust, dirt, formaldehyde, toxic fumes from paint-coating, etc. This has made this type of space heating very popular among people with severe allergies and multiple chemical sensitivity in Europe. Because far infrared technology does not heat the air of the room directly, and infrared rays are directional, only the person who is receiving directly the far infrared rays will feel warm in the room. Therefore, in the case of far infrared space heaters, it is extremely important to make a study of the room and place the far infrared panels directed to the places where people stay most of the time (sofa, dining table, bed, etc.).
Efficiency

Electrically-heated infrared heaters radiate up to 86% of their input as radiant energy.[5] Nearly all the electrical energy input is converted into infrared radiant heat in the filament and directed onto the product by reflectors. Some energy is lost due to conduction or convection.

For practical applications, the efficiency of the infrared heater depends on matching the emitted wavelength and the absorption spectrum of the material to be heated. For example, the absorption spectrum for water has its peak at around 3000 nm. This means that emission from medium-wave or carbon infrared heaters is much better absorbed by water and water-based coatings than NIR or short-wave infrared radiation. The same is true for many plastics like PVC or polyethylene. Their peak absorption is around 3500 nm. On the other hand, some metals absorb only in the short-wave range and show a strong reflectivity in the medium and far infrared. This makes a careful selection of the right infrared heater type important for energy efficiency in the heating process.

Ceramic elements operate in the temperature of 300°C to 700°C (572°F - 1292°F) producing infrared wavelengths in the 2000 to 10000 nm range. Most plastics and many other materials absorb infrared best in this range, which makes the ceramic heater most suited for this task.

[Rob]

So based on that wikipedia article unless your body is in the target area of the panel it's going to be cold, as the room's air temperature will be cooler, and it probably will be the case that the side facing the heater will be warm and the other side cool. You might need to put your furniture on a turntable so you cook yourself evenly