Air pumps and small bore piping

[Bouleversee]

My home, what I believe is called a ranch-style bungalow, quite large, was extended by our predecessors (almost doubled) and the new bit, which is where I spend most of my time, has a completely separate heating system which for some unknown reason (price of copper?) has pipes to the radiators which have a very small diameter compared with the usual size as in the rest of the house. The boilers must be getting on in years and looking ahead, I am wondering whether this would preclude the use of Air Pumps. 2 of those would be astronomically expensive to install and goodness knows where they could be situated so I think I would prefer gas boilers which could be converted to Hydrogen if and when that becomes available. I'd better have some sort of action plan in case one of my boilers packs up.

Are air pumps cheaper to run than gas boilers? I can't get my brain round how they work but then I don't understand refrigeration either.

[csearle]

My home, what I believe is called a ranch-style bungalow, quite large, was extended by our predecessors (almost doubled) and the new bit, which is where I spend most of my time, has a completely separate heating system which for some unknown reason (price of copper?) has pipes to the radiators which have a very small diameter compared with the usual size as in the rest of the house. The boilers must be getting on in years and looking ahead, I am wondering whether this would preclude the use of Air Pumps. 2 of those would be astronomically expensive to install and goodness knows where they could be situated so I think I would prefer gas boilers which could be converted to Hydrogen if and when that becomes available. I'd better have some sort of action plan in case one of my boilers packs up.

Are air pumps cheaper to run than gas boilers? I can't get my brain round how they work but then I don't understand refrigeration either.

I can't answer your question Lorna but what I feel I can say is that your fridge uses an electrical pump to transfer heat from one place (inside) to another place (the back of it). An air-source heat pump (ASHP), in a similar way uses an electrical pump to take heat from one place (outside) to another place (inside). The heat is free but the pumping uses (expensive) electricity.

With gas (cheaper than electricity usually) you just turn it into heat by burning it. Which of these is more expensive will depend upon the unit price of gas and electricity.

I do believe that the ASHP is cheaper at the moment but the amount of heat available is a function of the outside temperature and may not be able to warm even half of Bouleversee-Bungalows. Also your gas boilers provide your hot water. Unless you go for sophisticated (and even more expensive) installations your ASHPs will need to be augmented with something to provide hot water.

I am not an expert in all this so doubtless will have got some things wrong. Hopefully others better versed in it all will comment.

Chris

[staffordian]

I can't offer much in the way of help, I'm afraid, other than to say that it sounds as though your later system uses microbore pipes. This was popular for a while (not sure if it's still used) mainly, I think, because it was far easier and less intrusive to install. It could be bend more easily, came in long lengths so less joints were needed and smaller holes through walls etc were needed and, as you say, I suspect it would have been cheaper to buy too. We had it in a couple of houses, built in the 1970s to 1990s.

I don't think it's very highly regarded, but maybe Mike4 or someone with plumbing knowledge will correct me if I'm wrong on this.

Even with the little I know of air source heat pumps, I suspect microbore piping would be problematic. As air source heat pumps don't heat the water as hot as a gas boiler, radiators need to be larger to give out enough heat, and I suspect the limited size of microbore pipes would struggle to provide enough flow.

The other issue you may well already have read about is that unless a home is insulated to a very high standard, a heat pump will not provide enough energy to heat it. They rely on providing a low, steady amount of heat, ideally almost 24 hours a day in cooler weather. A poorly (or even averagely) insulated house will loose more than the heat pump can supply.

Your best plan B might be to budget to replace the existing boilers with gas ones before they are outlawed, looking for ones with a ten year warranty. By then, better, more efficient systems might be available.

[Breelander]

...the new bit, which is where I spend most of my time, has a completely separate heating system which for some unknown reason (price of copper?) has pipes to the radiators which have a very small diameter compared with the usual size as in the rest of the house.

Microbore is more commonly used these days as it's said to be more efficient.

The main benefit of the microbore system is that because the pipes are smaller. less water is carried through them, which in turn means less heat is lost as the water flows, leading to greater efficiency. The smaller pipes are also easy to bend and reshape whilst they are being installed making the more versatile and decreasing the amount of joints needed. (Joints can be prone to leaks and additional heat loss.) However, the small pipes can also be a major disadvantage of this system, particularly in hard water areas. The smaller pipes are more susceptible to becoming blocked which can cause a pump to wear out more quickly due to the fact it is working harder to try and pump water through the blocked pipes.

https://www.traderadiators.com/blog/wha ... ng-systems

Are air pumps cheaper to run than gas boilers? I can't get my brain round how they work but then I don't understand refrigeration either.

Some information and explanations here:

An air source heat pump costs more than a new gas or oil-fired central heating system. The typical cost ranges from £4,000-8,000, depending on the pump brand and its heat output. You’ll also need to pay for the installation cost. This could bring the total to between £5,000 and £10,000. If you’re fitting new underfloor heating or an air distribution system, you’ll need to factor in these costs too.....

....Air source heat pumps are one of the most efficient ways to heat your home, making the running costs far lower than what you’d typically pay for your heating system....

https://www.edfenergy.com/heating/advic ... pump-guide

[csearle]

A poorly (or even averagely) insulated house will loose more than the heat pump can supply.

I did come across an annex once (kitchen-diner, wet room, bedroom, and an attic bedroom) served by one air-source heat pump. (Hot water was electric.) It was in winter when I installed the power for it. I switched it on and in a very short time the entire building was toasty warm. It was of a design where warm air is circulated through it.

I was impressed mightily by it. No idea how much it cost to run. I put it on a 16A circuit breaker but it used less than that as it originally came with a plug-top. Anyway I did feel it could have handled a bit more volume. Mind you it supplied all the heat at one place so you would have to keep all the internal doors open!

Chris

[AsleepInYorkshire]

The air pump is ultimately the heat source. The size of the pipework inside the home will be dependant upon the distance from the heat source. The rate of flow in an air pump system is much faster than say gas or oil. Larger pipes are needed to achieve the flow rate.

Sizes range from 22mm to 42mm. I doubt micro-bore (or small bore) will be sufficient to run an air source heat pump system.

AiY

[Bouleversee]

Many thanks to all. You've said enough to confirm my feeling that air pumps are not the right way to go in this house. I suspect the insulation is not all that good and the radiators probably a bit undersized. Some of them are not getting hot enough which may be due to the pipes getting silted up (I am in a very hard water area) or because the thermostatic valves are stuck on some of them. There are 2 whose knobs I can't even turn and others where the pin seems to have stuck. I have a feeling the microbore pipes are not all that easy to flush either. I am going to book a service call in the near future. I definitely need water at a high temperature. I do have two h.w. cylinders which can be heated by the gas boiler or immersion (with rather long runs to kitchen and bathrooms) but I also have solid floors, much of them tiled. I'll keep the existing boilers going for as long as possible and see what developments there are in the way of hydrogen or convertible boilers before 2035. I may well be history by then anyway, leaving someone else with the problem.

I did read that the Swedish state-owned energy group is marketing an air pump which delivers water at the same temperature as gas boilers do but not marketed here yet. Apparently, it needs a very large water tank installed on a solid floor which could be a problem. Mine are up in the loft. I can't help thinking that installing heat pumps in existing premises will create a lot of problems.

[csearle]

...

There is a whole other thread here somewhere, which mentions these things I think. Standby...

[csearle]

...This one I think. C.

[Bouleversee]

...This one I think. C.

Thanks, Chris. I have read some of the posts but the rest of the 95 will have to wait till I have had some sleep.

[UncleEbenezer]

You're not considering a unified system for both halves of your ranch?

If not, what are the requirements? Do both halves have hot water (kitchens and/or bathrooms)? If not then you have the option of a heating-only system (no hot water) for one half, which may open the possibility of a lower-cost class of heat pump than the full Works. And things like a kitchen or a secondary shower room could heat their own water, with an instant-hot-water tap or electric shower.

Beyond that, can't say. Ideally you want a local tradesman you can trust.

[monabri]

You mentioned that some of the radiators are not getting warm enough. If the radiator is hot low down but noticeably cooler at the top ( you can tell by simply touching the radiator) then it might be a simple case of the radiator needing bleeding.

The valves (knob) which one turns can seize if closed if the radiator has not been used. The cost of a new valve.....

https://www.screwfix.com/c/heating-plum ... -_-trv#_=p

It's the labour which might be comparatively the higher part of the cost if they need changing.

[monabri]

Staffordian mentioned a Plan B above.

As a Plan B ( modified) you might consider buying a condensing boiler in a few years from now and putting it "on the shelf". Current cost c.£1000 / £1200

https://www.screwfix.com/c/heating-plum ... oilers#_=p


https://www.traderadiators.com/blog/wha ... -do-i-need

"The average combi boiler is available in one of four sizes 24-25kw, 28-30kw, 33-35kw and 40kw. As a rough guide most apartments and smaller houses, with up to 10 radiators will require a 24-25kw boiler.

A 28-30kw would be installed for a medium to large 3-4 bed house with up to 15 radiators, and a 33-35kw and a 40kw would be for a large house with anything up to 20 radiators."

[Mike4]

My home, what I believe is called a ranch-style bungalow, quite large, was extended by our predecessors (almost doubled) and the new bit, which is where I spend most of my time, has a completely separate heating system which for some unknown reason (price of copper?) has pipes to the radiators which have a very small diameter compared with the usual size as in the rest of the house. The boilers must be getting on in years and looking ahead, I am wondering whether this would preclude the use of Air Pumps. 2 of those would be astronomically expensive to install and goodness knows where they could be situated so I think I would prefer gas boilers which could be converted to Hydrogen if and when that becomes available. I'd better have some sort of action plan in case one of my boilers packs up.

Are air pumps cheaper to run than gas boilers? I can't get my brain round how they work but then I don't understand refrigeration either.

I can't answer your question Lorna but what I feel I can say is that your fridge uses an electrical pump to transfer heat from one place (inside) to another place (the back of it). An air-source heat pump (ASHP), in a similar way uses an electrical pump to take heat from one place (outside) to another place (inside). The heat is free but the pumping uses (expensive) electricity.

With gas (cheaper than electricity usually) you just turn it into heat by burning it. Which of these is more expensive will depend upon the unit price of gas and electricity.

I do believe that the ASHP is cheaper at the moment but the amount of heat available is a function of the outside temperature and may not be able to warm even half of Bouleversee-Bungalows. Also your gas boilers provide your hot water. Unless you go for sophisticated (and even more expensive) installations your ASHPs will need to be augmented with something to provide hot water.

I am not an expert in all this so doubtless will have got some things wrong. Hopefully others better versed in it all will comment.

Chris

I'm no expert on heat pumps either but from what I do know, I'd say Chris has everything broadly right above.

A couple of further points.

1) It is widely stated within the industry that heat pump only work in highly insulated homes. I've never really worked out why this is said, but I suspect heat pumps do not respond instantly to heat demand like a gas boiler does - I think they might take half an hour or so to respond. So I suspect rather than having an ordinary 'on/off' room thermostat, they run all the time and get modulated up and down. A well insulated house suffers less from internal temperature changes as the temperature outside goes up and down so their slow response matters less.

2) The temperature of the radiator water they produce is down towards the low 50's C. Existing rads connected to a gas or oil boiler will have been sized to suit a water temperature of 82C, so as you can imagine, existing rads don't work very well with the 54-ish C water delivered by a heat pump, so bigger rads are needed. Also, the flow rate through the new, low temperature rads needs to be higher apparently, so microbore pipework is inadequate and must be replaced with bigger diameter pipes.

Finally, another problem with heat pumps is the sheer size of all the gear that needs to be installed. Here is a pic of what gets put in, taken from inside the Worcester Bosch factory. Bear in mind this is a system that delivers hot water too so the thing on the left is a hot water tank, and the largest box on the right is the heat collector that goes outside in the garden.

[jackdaww]

My home, what I believe is called a ranch-style bungalow, quite large, was extended by our predecessors (almost doubled) and the new bit, which is where I spend most of my time, has a completely separate heating system which for some unknown reason (price of copper?) has pipes to the radiators which have a very small diameter compared with the usual size as in the rest of the house. The boilers must be getting on in years and looking ahead, I am wondering whether this would preclude the use of Air Pumps. 2 of those would be astronomically expensive to install and goodness knows where they could be situated so I think I would prefer gas boilers which could be converted to Hydrogen if and when that becomes available. I'd better have some sort of action plan in case one of my boilers packs up.

Are air pumps cheaper to run than gas boilers? I can't get my brain round how they work but then I don't understand refrigeration either.

======================================

there is nothing basically wrong with small bore piping , the water pump speed may have to be cranked up a bit .

i installed our heating system many years ago using 10mm flexi copper tube. it feeds some pretty big radiators including the hot water tank.

i dont like the sound of heat pumps one bit .

[Nocton]

Have a look at electric heat batteries. https://www.caldera.co.uk/

We are just in the process of replacing our oil boiler with one. An air source heat pump would require major changes to our radiators and possibly even the installation of underfloor heating. With the heat battery system nothing changes internally so the overall cost is lower than a heat pump. Ultimately the system will run on 'surplus' electricity switched smartly by the elec co. But at present, with the high prices, we are sticking with Economy 7.

Our house was built in 1999 and has small-bore pipes, which I've always assumed are the most up-to-date.

[bungeejumper]

I've done quite a lot of looking into air source heat pumps, and I'm convinced that they'll be the perfect solution. One day. At present the main units are too large and too loud, and in general they're quite badly suited to closely-packed housing or to listed/protected zones where the planning rules often make it practically impossible to fit them without contravening one law or another. (Typically, the noise nuisance rules.)

But ASHPs are getting better with every passing year. Quieter, smaller, and with better refrigerating gases that enable them to work more efficiently. I'll be buying one in ten years' time , but if I had to buy something right now it would be another gas boiler, just for the interim period.

Like some other posters, I doubt that microbore pipes are an insuperable obstacle to anything. All they need is a really strong pump. For ASHPs, however, it's sometimes necessary to replace certain radiators with bigger ones, because they run at lower temperatures than you're used to. Or, alternatively, just more of them.

BJ

[Bouleversee]

You're not considering a unified system for both halves of your ranch?

If not, what are the requirements? Do both halves have hot water (kitchens and/or bathrooms)? If not then you have the option of a heating-only system (no hot water) for one half, which may open the possibility of a lower-cost class of heat pump than the full Works. And things like a kitchen or a secondary shower room could heat their own water, with an instant-hot-water tap or electric shower.

Beyond that, can't say. Ideally you want a local tradesman you can trust.

Kitchen and living rooms in the centre of the house, bathroom and bedroom(s) at each end. One boiler at far end of loft at one end, the other on far wall of garage at the other. one hw cylinder in hall cupboard at centre of house, the other in cupboard in breakfast room, adjacent garage. I can see the need for 2 systems.

[Bouleversee]

You mentioned that some of the radiators are not getting warm enough. If the radiator is hot low down but noticeably cooler at the top ( you can tell by simply touching the radiator) then it might be a simple case of the radiator needing bleeding.

The valves (knob) which one turns can seize if closed if the radiator has not been used. The cost of a new valve.....

https://www.screwfix.com/c/heating-plum ... -_-trv#_=p

It's the labour which might be comparatively the higher part of the cost if they need changing.

Thanks, Mon. I did actually know all that and check for air regularly. It's def. not that. If anything, they are cooler at the bottom which could mean sludge. Some of the valves are Drayton Lifestyle which I think are rubbish. I never had any problems with valves in 35 years at our previous house but the pins are always sticking and now the knobs won't move on 2 of them. I want to get them changed for better quality.

[richlist]

This thread seems to be focusing on wet systems. Air sourced heat pumps that provide blown hot or cold air are excellent & don't require radiators or pipework. They can also be used as air conditioners in the summer months. Worth consideration.