Anything special about radiators for an air source heat pump?

[Gerry557]

Consider if you need more instant heat or slower more efficient heat. I had a large family room with x3 rads but took a while to heat up. During the revamp I swapped to x2 designer rads with more output. It looks nicer but can get from cold to warm in 15min now, so a more usable room.

The need for quick heat is because of poor build quality. With good insulation and good airtightness, you might only lose a degree or less a day. With good construction there's little reason not to maintain the temperature 24/7, and you won't/can't have different rooms at substantially different temperatures.

You can't apply the norms for a Victorian retrofitted with central heat to decent quality modern construction. Everything works differently. When you apply the wrong norms for the actual construction everything works poorly. With a modern home designed to be heated with a heat pump there it is likely that almost everything you hear is from people who are living in and talking about houses that are completely different from your own.

Im not sure that particular room is energy efficient and there is a lot of glass and high ceilings. It is often out of use for long periods. It has underfloor heating which is great once up to temp. Plus its near your feet. Whilst than might be efficient it takes a couple of hours to get up to speed on a day like this. So if we have visitors we need something more instant. There are plans to swap to triple glazing which might improve things.

Im sure more modern designs can be almost energy free. I improved the insulation in my media room, more for sound quality reasons but just having the TV on provides enough heat generally.

Hopefully new builds will have a lot more insulation and energy efficiency considerations but that doesn't make it "affordable"

[DrFfybes]

There are plans to swap to triple glazing which might improve things.

We looked at that when we refurbed last year.

Both companies offered it, and both advised against it except for the lounge picture windows.

Cost in both cases was circa 30% more, however there were limitiations with the frame as it is deeper and would not match existing ones, and also the extra weight has caused problems with hinge strain on large openers, which we needed for 2 of the bedrooms. I suspect this is more down to the use of budget hinges, but they did say top openers were a better option.

However the difference in performance is so obfuscated it is untrue, a web search gives R values of 1.1 for DG and 2.0 for TG, yet another claims R values of 6-8 for TG and a 60% decrease in heating bills - presumably only if the property is a commercial greenhouse. https://www.glazingrefurbishments.co.uk ... le-glazing

The savings from the 4m2 of glass compared to the 8m2 of bifold doors and 30m2 of external brickwork are probably pretty minimal so we had insulated board dabbed onto the external walls instead.

Paul

[9873210]

The need for quick heat is because of poor build quality. With good insulation and good airtightness, you might only lose a degree or less a day. With good construction there's little reason not to maintain the temperature 24/7, and you won't/can't have different rooms at substantially different temperatures.

You can't apply the norms for a Victorian retrofitted with central heat to decent quality modern construction. Everything works differently. When you apply the wrong norms for the actual construction everything works poorly. With a modern home designed to be heated with a heat pump there it is likely that almost everything you hear is from people who are living in and talking about houses that are completely different from your own.

Im not sure that particular room is energy efficient and there is a lot of glass and high ceilings. It is often out of use for long periods. It has underfloor heating which is great once up to temp. Plus its near your feet. Whilst than might be efficient it takes a couple of hours to get up to speed on a day like this. So if we have visitors we need something more instant. There are plans to swap to triple glazing which might improve things.

Im sure more modern designs can be almost energy free. I improved the insulation in my media room, more for sound quality reasons but just having the TV on provides enough heat generally.

Hopefully new builds will have a lot more insulation and energy efficiency considerations but that doesn't make it "affordable"

If you really only use the room occasionally the solution to heating it up rapidly is a couple of three bar electric fires (resistance heating). You'll pay a several pounds every time you do that, but if it really is occasional, it's not a big deal,

My gripe is that expectations, and language, based on ancient designs, is preventing adoption and proper use of modern efficient designs. Things like hot air systems and air-to-air heat pumps are ruled out for new construction simply because they can't be used to retrofit 1900's construction. No low temperature heat pumps with small radiators and well insulated buildings just because they were unknown to George VI. I know people who put on-demand hot water systems on a timer, so they are off while they are not home. A house which was built to, and actually attained, 1980 standards works quite differently from the way something designed to be heated with fireplaces does.

Also a lot of retro-fits should be done with a bulldozer. They were faff when they were built, and no matter what was done with them since they are still faff. Time to redesign around electric lights, indoor plumbing and central heating.

[Gerry557]

But the new rads work fine. It was just an example of what could be done by considering the outputs and changing to suit you needs.

I had considered adding extra insulation but assumed on the inside maybe I should look at external boards.

[88V8]

I had considered adding extra insulation but assumed on the inside maybe I should look at external boards.

Even assuming you live in an ugly modern box and have no architectural features to preserve, that's a very expensive way of insulating. Detailing around door and window reveals, eaves, gutters and downpipes, drains.

V8

[csearle]

I had considered adding extra insulation but assumed on the inside maybe I should look at external boards.

A local builder I know prefers insulation to be on the outside (mind you he does this on new extensions rather than retrospectively upgrading). He told be that the advantage is that indoor heat gets stored in the masonry (he uses some especially dense stuff) such that you can open the doors, letting the heat out and after closing them again the air warms back up. In this way the interior stays at a fairly uniform temperature. C.

[Urbandreamer]

I had considered adding extra insulation but assumed on the inside maybe I should look at external boards.

A local builder I know prefers insulation to be on the outside (mind you he does this on new extensions rather than retrospectively upgrading). He told be that the advantage is that indoor heat gets stored in the masonry (he uses some especially dense stuff) such that you can open the doors, letting the heat out and after closing them again the air warms back up. In this way the interior stays at a fairly uniform temperature. C.

At one time I was very interested in solar heating, and in particular passive solar heating.
The idea is that sun heats stuff with a high thermal mass, which gives up it's heat when the sun goes down.

There are advantages and disadvantages to the idea of using thermal mass. Obviously it's the way storage heaters work. However unlike them it's part of the fabric of the building. This means that if your building is unused/unheated, for example while you are at work, then it takes far longer to heat up.

Alternatively if you use the building all day, then as said, it's easier to maintain a fairly uniform temperature that is slow to change.

[9873210]

At one time I was very interested in solar heating, and in particular passive solar heating.
The idea is that sun heats stuff with a high thermal mass, which gives up it's heat when the sun goes down.

There are advantages and disadvantages to the idea of using thermal mass. Obviously it's the way storage heaters work. However unlike them it's part of the fabric of the building. This means that if your building is unused/unheated, for example while you are at work, then it takes far longer to heat up.

Alternatively if you use the building all day, then as said, it's easier to maintain a fairly uniform temperature that is slow to change.

If I remember correctly the thermal capacity and conductivity mean that for moderate temperature swings (say 5-10 degrees C) only the outer cm or so of plaster actual responds significantly to daily temperature swings. Deeper material such as brick would only come into play over longer periods of several days or weeks. For daily temperature control it does not matter much if the plaster is over brick, Styrofoam, metal, or even an air cavity (as long as the air is captive and not convecting heat outside the cavity). Since most walls are coated with a cm of plaster this means most walls respond the same to daily temperature swings.

Storage heaters use air channels in the ceramic so that more of the material is near the surface and able to interact on short time scales. They also use much larger temperature swings. Most importantly actively controlling the airflow controls release of the heat.

[csearle]

Storage heaters use air channels in the ceramic so that more of the material is near the surface and able to interact on short time scales.

Might be the case for newer ones but the standard Dimplex ones that I occasionally decommission have no air channels at all. Each half of the brick has the shape of the heating element formed into it, which then snugly fits around the element when they are assembled, making effectively a solid block. C.