Air source Heat Pumps any good?

[Skydivermel]

Turn the taps on. If the hot and the cold come out at the same rate, it's probably unvented.
Turn the rising main off - if you've still got hot water it's vented.

What he said

 

[Misterdog]

I've been in the industry for 27 years. There are many factors to consider prior to making an informed decision. Don't listen to you mate down the pub who has watched a YouTube video on ASHP.

I installed a state of the art Ideal Logic condensing boiler some 7 years ago (a superb piece of engineering by the way).

The sales patter at the time told me that condensing boilers were 90/95% efficient as compared to my old Worcester Bosch 'standard' boiler at 70/80%.

What the sales/marketing patter did not inform me of was that in 'non condensing mode' the boiler was only operating at around 70/80% efficiency. Think car (ICE) on choke until the engine warms up.

One of the 'benefits' of this smart boiler is that it has a display showing a raft of information (I assume to be correct).


I have just accessed the data which informs me that during it's lifetime my condensing boiler has been in condensing mode for 55% of it's burn time........

So for nearly half the time it has been running, it has been at near the efficiency of my old boiler. efficiency wise.

'Wise sages' will tell me that I need weather compensation control,
larger radiators or to run the system 24/7 to get the return temperature down and increase the efficiency.

A good salesman can convince you of anything,It's their job

I fitted WCC 2 months after I installed the boiler... so it is included in the stats provided above.

So how much has my boiler change saved the planet ?
very little I suspect.

How much has boiler change saved me over the last 7 years .

Sod all basically - though it is a superb piece of engineering with useful diagnostic software, I assume to be accurate.

I have a friend who invested in an ASHP some 7 years ago it broke down, no one could fix it he so he fitted a condensing combi boiler.


Beware the sales/ marketing/green claims is my advice.


Turn down your heating thermostat to a sensible level 17/19C
and wear an extra thermal layer or even a wooly hat if you really wish to 'save' the planet.

A 1 degree reduction on your heating stat =10% reduction in your heating bill. - ish.

All real life scenarios not from a mate down the pub

Anyone wishing to give me £ 10/20 K I can 'promise' that you will be saving the planet and your wallet over the long term.
DM me for details.................

 

[Misterdog]

If Govt gave grants for the correct insulation then we could all run ASHP. BUT if insulating to a very high degree then we have the issue of moisture retention which leads to the necessity of the correct ventilation system for the property.

If only the government would give me £ 100 K I could do that.

Outrage.

 

[Chris70]

Turn the taps on. If the hot and the cold come out at the same rate, it's probably unvented.
Turn the rising main off - if you've still got hot water it's vented.

#Phil Pascoe Thanks!

 

[deema]

Thanks everyone, heat pumps are definitely now on the maybe one day pile.
What I was surprised by, because I hadn’t looked into it before is that oil has a much higher BTU/ litre than LPG, approximately 1.5 times. Price wise oil is usually close to lpg. No brainier which is the more economical to run. I’m on oil in my present house.

 

[MikeJhn]

We had oil central heating installed over thirty years ago and it's still on the same CI boiler, my Testo 327-1 gas analyser tells me I am running at 86% efficiency, think I will keep it.

Solid flint walls so no chance of insulting them.

 

[Pedronicus]

my Testo 327-1 gas analyser tells me I am running at 86% efficiency, think I will keep it.

With respect the analyser is showing the efficiency of combustion not the efficiency of heat transfer from the boiler to the heating system or from the heating system to the property both of which will be considerably lower.

 

[MikeJhn]

Perhaps so, but how else do you measure the efficiency of a Cast Iron boiler, I think the efficiency of combustion is close enough, temperature setting on the boiler and water temperature seem to correlate, as do flow and return temperatures that also indicate an efficient system.

 

[Pedronicus]

Perhaps so, but how else do you measure the efficiency of a Cast Iron boiler, I think the efficiency of combustion is close enough, temperature setting on the boiler and water temperature seem to correlate, as do flow and return temperatures that also indicate an efficient system.

From the data badge you read the input power and the output power. Those figures will give the efficiency that the manufacturers designed the boiler to work at. You will find that it is nowhere near the combustion efficiency of 86% which, as I have said, is not the same as the output efficiency of the boiler.

 

[Spectric]

I think it earns a massive efficiency rating just because it has delivered for thirty years, that makes it resource efficient unlike so many modern combi boilers that can become beyond economical repair after eight years.

The solution to our energy crisis is to build houses with decent insulation and high thermal efficiency, yet we continue to just build these sub standard sheds because the shareholders want good returns. Again our problems come down to greed and not delivering for our future needs.

 

[XTiffy]

Spectric, If what you say is true (sub-standard sheds), then that is a failure of Building Control. I have built four houses in the last 18 years and the insulation requirements have increased massively. Such that cavity width has increased above the often standard 100mm or four inch in the past, to enable greater thickness of insulation. Air tightness regs. have likewise increased. Condensation will be the next big bad wolf! Where the problem lies is developers using cheap barely trained tradesmen for building. I pity the poor buyers who face long snagging lists due to incompetent tradesmen.

 

[rogxwhit]

developers using cheap barely trained tradesmen for building

Indeed, and there are two aspects in fact - one is training and the other is motivation. I mean personal motivation to understand the task and do it well.

Insulation is undoubtedly key but can be installed badly so that it won't perform to its potential. It's great merit is that once installed it is passive and should last the life of the building without further input. In contrast, all high-tech heat sources - boilers, heat pumps, pellet stoves, etc, have a quite modest life expectancy.

 

[MikeJhn]

From the data badge you read the input power and the output power. Those figures will give the efficiency that the manufacturers designed the boiler to work at. You will find that it is nowhere near the combustion efficiency of 86% which, as I have said, is not the same as the output efficiency of the boiler.

Then how do you measure the output efficiency of a modern CH boiler on it's annual service, or is the manufacturers data just quoted as a matter of course?

 

[Pedronicus]

that is a failure of Building Control.

Sadly most LBC departments are now outsourced to private companies who tend to be subject to "commercial pressures"!

 

[D_W]

Thanks everyone, heat pumps are definitely now on the maybe one day pile.
What I was surprised by, because I hadn’t looked into it before is that oil has a much higher BTU/ litre than LPG, approximately 1.5 times. Price wise oil is usually close to lpg. No brainier which is the more economical to run. I’m on oil in my present house.

LPG and propane here are generally a little more expensive per btu than oil, too, but they do have some side benefits:
- almost nothing to clean in a furnace
- if you want a gaslog fireplace, you can run that, too, which turns out to be relatively efficient if you're living alone and can heat a small area to it and turn down the rest of the house.

GSHP is replacing oil and propane an ASHP here pretty quickly. ASHP is the cheap option in a lot of new construction. Your boilers may be different than the typical oil boilers here, but the oil here is diesel #2 and furnaces generally need an annual service/cleaning and are really gummed up by then. Not hard to do on your own if you have access to the proper brushes and convince the service guy to let you watch a round. But filthy.

I've had a gas furnace in the house for going on 17 years. It was here for 23 years before I got here and is still probably very close to its efficiency rating (80%) and it has been checked four times, but never needed any service. Because the A/C that it's mated to uses an older refrigerant that would now cost $1500 to charge, it's going to have to go this spring. I'm not easily convinced that it wouldn't continue to run longer than a new furnace will last, but the A/C is running hard enough to cost an extra $150 a month in electricity with dwindling coolant.

GSHP costs about the same as gas for heat here, the units are complicated (electronically) and service is expensive of one of the boards has problems (FIL and BIL have units that each have four separate PCBs in them and the service guys have trouble diagnosing them and getting the right parts. it sounds like they try to be all things to all people all the time with complex functionality.). In the summer, though, they are super efficient and most of the places where they're popular are folks off the gas grid. Oil and propane probably cost double on average vs. ASHP and piped natural gas.

 

[mc281]

I’ve been asked by the head of our household to look into air source heat pumps. We are hopefully moving shortly, and she would like to have an eco friendly heating system in the new residence. I’ve done a little bit of research, and it would appear that financially they don’t financially make any sense even including the £5K government grant available.
My initial work looked at the Kw/H generated from 1 litre of oil and 1 cu ft of gas, I’ve used 60% and 90% boiler efficiency to work out how much it will cost for 10.35Kw of heating energy (equivalent to 1 litre of kerosene which my existing property uses). I’ve looked at heat air source heat pumps and used the optimistic 300% efficiency, however, my reading suggests that this drops down to say 200% (and lower) which I haven’t used) when the air is cool in Winter. The saving with todays high energy costs means that it won’t break even for say 15 years. In fact if the house is highly insulated I will be dead before it breaks even. If I look at energy prices before Ukraine, and oil is going back down in price, the payback is again ridiculous / if ever.

It seems that an efficient air source system needs to run as c40C which is too low for hot water so you need an immersion heater to top up the hot water tanks to stop legionnaires growing (which isn’t I believe included in the 300% efficiency figures quoted). The radiators need to be much larger than for a gas / oil boiler and preferably it should be underfloor if you are to attain the same room temperature. Now my wifey likes it warm (a career running hospitals has made her acclimatised to the heat before anyone suggests running the house at a lower temperature)…..around 22C which isn‘t a big temperature differential for a 40C system, I’m actually wondering in a house that may not be very thermal efficient if it will be possible to attain this room temperature.

Has anyone else looked at how cost effective moving to air source is? Am I missing something?

Whats people experiences, the good the bad and the down right ugly in installing and running such systems?

Heat pumps have a problem which seldom, if ever, gets mentioned.... The start up current is higher than the running current requirement and this surge on the mains infrastructure is very high. This causes voltage drops and pulses which affect the supply stability to surrounding homes during that period. It affects much electronic infrastructure too. This is made worse by inadequate cable capacity in the street and the further distribution network.
Now add to that the extra current needed to charge electric vehicles and you have a recipe for a worsening situation.
We are slowly, but accelerating, disappearing up our own orifices and we can feel the manipulation we are subjected to if we stop for just a moment or two to think about it. Unfortunately we haven't got time because we need to work even faster to just keep up.

 

[Agent_zed]

I think it earns a massive efficiency rating just because it has delivered for thirty years, that makes it resource efficient unlike so many modern combi boilers that can become beyond economical repair after eight years.

The solution to our energy crisis is to build houses with decent insulation and high thermal efficiency, yet we continue to just build these sub standard sheds because the shareholders want good returns. Again our problems come down to greed and not delivering for our future needs.

Its not even a case of more insulation. If house builders bothered to think beyond the shareholders they could build houses that have huge efficiencies just by there placement. If the majority of new builds faced south they would benefit from passive solar gain. Of course you don't want red hot houses in summer so you put large overhangs so in summer it is shaded and in winter with lower sun you get the gain. You also have green roofs which cool in summer and insulate in winter, and would add to green space in a development reducing the heat island effect of huge amounts of tile and tarmac. solar panels and heat pumps and you'd barely have an energy bills

The above is so so simple but instead we get 1950's style houses built as close as possible to each other with no thought whatsoever. Instead in summer they get red hot and everyone has to run A/C units and in winter have the heating on continually.

 

[mc281]

Its not even a case of more insulation. If house builders bothered to think beyond the shareholders they could build houses that have huge efficiencies just by there placement. If the majority of new builds faced south they would benefit from passive solar gain. Of course you don't want red hot houses in summer so you put large overhangs so in summer it is shaded and in winter with lower sun you get the gain. You also have green roofs which cool in summer and insulate in winter, and would add to green space in a development reducing the heat island effect of huge amounts of tile and tarmac. solar panels and heat pumps and you'd barely have an energy bills

The above is so so simple but instead we get 1950's style houses built as close as possible to each other with no thought whatsoever. Instead in summer they get red hot and everyone has to run A/C units and in winter have the heating on continually.

What an ABSOLUTE load of common sense!

 

[Spectric]

If house builders bothered to think beyond the shareholders they could build houses that have huge efficiencies just by there placement.

There lies the problem, many of these property tycoons are party donors and have a large influence on political decisions, making money is more important than building decent homes for the future so they get away with throwing up sheds. This is more than likely why our building regs have not be modernised to reflect the changes needed and why these developers just cram as many sheds onto a piece of land without thinking at all about location. When you look at these dormatory developments they are packed in so even a south facing shed is in the shadow of others.

 

[AJB Temple]

But is this true Spectric? Or are you merely stating a form of prejudice based on out of date experience? if you read current building regulations that came into force from June 22, there have been definite measures to improve U values, insulation, air leakage etc. Lenders have also begun to change policies to favour lending on well insulated homes (according to MSM recently), and consumer behaviour is bound to change (or has already) given recent massive price increases for energy. Everyone I know who has bought property in the past year or two (maybe 8 people) has been very focussed on the efficiency of the property.

Modern building methods are also changing quite rapidly with interlocking thermal blocks, insulated prefabricated wall panels etc. I have watched a number of new builds go up near us in recent years. Whilst there was a bit of a rush to get some done before new regs came into force, the standard of insulation in houses currently being built near us in Kent is far higher than it was a decade ago. The standard of finishing is very variable though.