Foil sheet behind rads

k123456

Will be getting house renovated and will be possibly putting in new rads

Hoping to make house more energy efficient

Is it worthwhile putting foil sheets behind rads,
this has been done for years, is there a better way to do this

What is the latest technology I should look out for in rads, heating systems. Will be using gas, house four bedroom semi

Is it best to not position rads under windows

DGOBS

I would have said under a window is the best place to install them IMHO

Foil sheet do work, but to gain any real effect, they would need to extend 150mm at least above the rad, not very pretty

LIFFY FISHING

You are wasting your time and money putting foil brhind radiators, radiators work on heat convection which means hot air rises, heat rises it doesent go backwards, rads under windowd helps the thermal air flow move heat convection around your rooms, just make sure you have your walls and windows properly insulated.



Quote=k123456;80964569]Will be getting house renovated and will be possibly putting in new rads

Hoping to make house more energy efficient

Is it worthwhile putting foil sheets behind rads,
this has been done for years, is there a better way to do this

What is the latest technology I should look out for in rads, heating systems. Will be using gas, house four bedroom semi

Is it best to not position rads under windows[/Quote]

DGOBS

So radiators give no radiated heat? at all? since when? about 20% is radiated heat, but as I said the foil that was used 'for years' was pretty useless, as it would need to extend above the rad to really work at all. (insulation to high standard is a given?)

paddy147

k123456 wrote: »

Will be getting house renovated and will be possibly putting in new rads

Hoping to make house more energy efficient

Is it worthwhile putting foil sheets behind rads,
this has been done for years, is there a better way to do this

What is the latest technology I should look out for in rads, heating systems. Will be using gas, house four bedroom semi

Is it best to not position rads under windows

Forget them.

50mm or 80mm insulated plasterboard on the walls and then fit the rad brackets and rads with 100-120mm frame fixers.

Insulate the roof/attic spaces.

Fit Energy effiecent windows in the house

Install Solar system for hot water too.

Job Done.:)

sethasaurus

DGOBS wrote: »

So radiators give no radiated heat? at all? since when? about 20% is radiated heat, but as I said the foil that was used 'for years' was pretty useless, as it would need to extend above the rad to really work at all. (insulation to high standard is a given?)

What you guys call 'rads' or 'radiators' are not radiators at all. They are convection heaters.
There is only a very small amount of heat radiated (much less than 20%).

If you want more radiated heat you could paint them black.

It seems ludicrous to install them underneath a window unless they're really well-insulated and sealed windows..

air

sethasaurus wrote: »

It seems ludicrous to install them underneath a window unless they're really well-insulated and sealed windows..

At first it sounds crazy but it actually makes perfect sense.
The window is normally the coldest surface in the room so air in contact with it rapidly cools and falls downward where it is reheated by the radiator.
If the radiator is located elsewhere this (inevitable) cold air has to travel across the room to the radiator's location. This then means that no matter how high a temperature you heat your room to, you will have cold air currents (cold draughts!) moving around the room. This just leads to people increasing temperature setpoints etc which further increases energy consumption with little consequential improvement in comfort level.

sasol

I put in these foil sheets behind the rad.

My advice to you would be to spend your money on something else. I did not notice a blind bit of difference after they were put.

paddy147

My father said something to me in the past when it came to house rennovations,making things better and money............


"Short term pain for long term gain"


Just my 2 cents worth.:)

DGOBS

I am not suggesting you do it, but just pointing out that they never worked as they would have to be protruding at least 6 inches above the rad to have any effect.

In 3 words, insulation, insulation, insulation...and if you can afford it...more insulation

k123456

Thanks for all the replies, folks, very useful info

Energy efficient windows, what features do I need to look out for

Triple glazed, good idea or not, worth the extra money, is it best to install everywhere or just north facing windows

Outkast_IRE

k123456 wrote: »

Thanks for all the replies, folks, very useful info

Energy efficient windows, what features do I need to look out for

Triple glazed, good idea or not, worth the extra money, is it best to install everywhere or just north facing windows

In terms of value for money , the windows if you already have double glazed should be the last thing on the list.

Be more concerned with insulating attic and walls first , then start thinking of floor.

im invisible

sethasaurus wrote: »

If you want more radiated heat you could paint them black.

how would that work, exactly?

sethasaurus

At first it sounds crazy but it actually makes perfect sense.
The window is normally the coldest surface in the room so air in contact with it rapidly cools and falls downward where it is reheated by the radiator.
If the radiator is located elsewhere this (inevitable) cold air has to travel across the room to the radiator's location. This then means that no matter how high a temperature you heat your room to, you will have cold air currents (cold draughts!) moving around the room. This just leads to people increasing temperature setpoints etc which further increases energy consumption with little consequential improvement in comfort level.

You're only setting up a very lossy loop with the enormous heatsink we call Jack Frost (via the window) and your heater. If you want to pump energy into this, then you deserve to have a massive heating bill.

Also, a lot of people use curtains to stop the cold air from the window. Unfortunately, I've seen a lot of heaters below windows, with curtains pulled in front of them (long curtains covering the heater as well). Don't make that mistake.

im invisible wrote: »

how would that work, exactly?

Strangely enough, it's called black body radiation.
Don't go thinking you're going to magically get extra heat though..


Just to add: Double glazing is great, but if you neglect other things, then you're just fixing 6 holes in a 12-hole bucket.
The house I moved into recently was (badly) renovated about 5 years ago. Many of the expensive double-insulated windows are broken through wear and tear. That seems a short lifespan, but it comes down to a combination of lack of lubrication on the sliders (alumium corrosion) and people just forcing the window closed.
Unfortunately, there is no insulation in the kitchen or bathroom walls or ceiling, so going to the toilet in winter is like stepping into a meat-locker (all nicely tiled in white).

Oh yeah, and foil behind the heaters? Forget about it, unless you want the nice shiny panel as some kind of wacky aesthetic feature.

sethasaurus

Don't forget to insulate your hot water tank and the pipes too!

It takes about 3 minutes to get hot water from our 'immersion' to the kitchen sink.

Gurgle

DGOBS wrote: »

In 3 words, insulation, insulation, insulation...and if you can afford it...more insulation

Once you've sealed all the sources of drafts...

air

sethasaurus wrote: »

You're only setting up a very lossy loop with the enormous heatsink we call Jack Frost (via the window) and your heater. If you want to pump energy into this, then you deserve to have a massive heating bill.

Heat loss through the windows will increase slightly due to the locally higher air temps caused by the rad, however the elimination of draughts more than compensates for this.
You are exaggerating to a huge extent by implying that any house with rads under the windows (every house with rads I've ever seen) will have a massive heating bill.

sethasaurus wrote: »

Also, a lot of people use curtains to stop the cold air from the window. Unfortunately, I've seen a lot of heaters below windows, with curtains pulled in front of them (long curtains covering the heater as well). Don't make that mistake.

This is a separate issue, my own personal preference is for window dressings that fit into the ope. I agree that curtains that come down over the rads are non sensical.

cikearney

These foils may have appered to work with, as on of the guys said "radiators", back in the day, and as he also said we now have heat convectors which are designed to create a convection current within the room, meaning to pull the cold air down and sending the warm air uo creating a current. and besides all of this "heat rises".