UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

betsc

I'm sorry I left this hanging, just a lot going on.

My house is insulated better than the 1998 standard but not up to today's probably. I handle the draughts and keep the house ticking over at a lowish temp - around 18-19 for the two rooms I use mostly and 16-17 for all the rest. Wish I could tell you what my better half does but my better half is contained within my own body( rather than in another human's), and is often inaccessible to me!.

The technical stuff (SAP) throws me. I did look up my average usage over last year and it was around 26kwhs a day. Now that my energy-guzzling son is gone it ought to be lower on average. Maybe this was a glitch between the very cold weather and the system settling in. But if anyone has a rough idea what they use in a cold period in a largish house, I can at least make an unscientific comparison.

Usage dropped as temps rose, but I'm still measuring.

Thank you, Geotherm, deano77 and John_P, for trying to answer my ridiculous question!

andytanner

First of all thanks to all for the contributions. The amount of confusion over air source is plain to see. I wondered whether I could share my experience so far.

I have a verbal quote which I am happy with, but we will share that later.

My situation. I have a three bed house with a 22 year old oil combi boiler which is dying less slowly than I would like. We are not on mains gas and can't get it here in the village.

I have done calcs on the house and the heat loss is 7Kw.

Like many here I have had many interesting conversations with installers who think that massively overcharging is the way forward. I have been quoted between £8.5K to 11K for a 9Kw Air source heat pump from 5 different "eco" companies who you will find if you look for heat pumps on the web.

I like to know what I am buying and after a while I narrowed it down to Samsung / Daiken / Mitsibushi and started having some interesting conversations where I started deconstructing the price with these companies to understand where the money was going (they don't like this process BTW - be strong refuse to be diverted). Imagine my surprise when I started learning that the heat pumps (from almost everyone) are about £2.5K (ebay) or less out to trade (for this size). Now I need an indirect unvented cylinder to replace the old combi function and of course that is expensive too as it is a effectively a pressure vessel. After more fishing about you can get a Gledhill Heat Pump indirect cylinder 250litre for £680 (ebay). There are a few bits and bobs such as valves and gauges, but really they don't cost a fortune. Incidentally a lot of these come with the Gledhill as standard.

So if we say a trade should be £150-£180 a day and it is 2 guys for 2 days, plus commissioning and the MCS paperwork you might wonder where the extra £4k to £6k is going. I was.

I then called one of the manufacturers and had a chat asking why every person I call is after a premium price and won't move much (at this point I was beginning to think it was me). They gave me a gem of advice - use an air conditioning company. The market is more established, the idiots have mostly been stripped out of the industry leaving established players who are more efficient and while they are looking for a profit are not looking to retire to a Caribbean island tomorrow on my money. The technology is effectively the same and the good ones have or are going through the process of the MCS certification.

Now at this point you could be forgiven for thinking I work in the a/c industry. I don't. Never have and none of my friends or family do either.

BUT - suddenly I am having a sensible conversation with an a/c company who are one of the leading 6 suppliers in the UK (Part of Samsung's "Super 6"). Really nice MD, we have a chat through and we have agreed verbally 9Kw Monoblock system paired with 210 Gledhill Indirect Unvented for HALF of what I have been quoted elsewhere (under £5,000). Complete, delivered and all MCS registration.

Now I know I am coming across as unbelievably tight, but I wanted to help others look in the right place first rather than get frustrated with poor and greedy suppliers. If anyone wants the supplier details please message me and I will give contact info.

I do want some help from the forum though. The energy saving trust said the trials were mixed. Our house is 1926 but the walls were insulated last year and the loft is 400mm to 450mm, double glazed all round. All the radiators are massively oversized (over 50%) as I replaced them 5 years ago and I knew I wanted to give myself some leeway on technology. So I can run them quite cold (35 to 40 degrees). Heating can be supplemented by wood burner in lounge.

Will my bills go down from using oil? Or am I going to get a massive shock with my first electricity bill (current supplier OVO)

Also can I get a better tariff with this heating and can I get economy 7 and is it worth it?

All help appreciated,

Thanks

Andy

nande2000

Depends on a lot of things, mild or cold winter, how hot you like your house, etc.
Mitsubishi do a good calculator that will take you through all this and give an estimate of running costs. Any installer worth their salt should walk you through it and be honest about where cold spots may occur in your house.

Run away from anyone who lets you choose all the kit and has a 'we wont know till we put it in' attitude.

I have an 8.5kw Ecodan with wood burner backup and it heated the house fine at -7 ambient a week ago. Its early days for me but my heating bill looks to be cut by 30% (previous boiler was oil and 70% ish efficient.)

Remember to get an MCS accredited installer.

Cardew

andytanner wrote: »

First of all thanks to all for the contributions. The amount of confusion over air source is plain to see. I wondered whether I could share my experience so far.

Welcome to the forum, and what an excellent post!

As you might have seen from my previous posts I am a big critic of the whole ASHP 'industry' - but not the technology.

The manufacturers will sell their equipment to virtually anyone and then pass the buck to the installers.

If your house is unsuitable for an ASHP, do you think any installer is going to tell you, and lose the sale?

You have already detailed the huge profit margins in your post - up to £11k using existing radiators!

Your choice would appear to be to replace the oil boiler at a cost of £2,000 - £2,500? or an ASHP for £5,000.

At current oil prices, with a new oil boiler, you will be paying around 7p/kWh.

So taking electricity prices at 12p/kWh you will just about be in profit if you can get an overall annual COP of 2.0 - which should be easy to achieve; however bear in mind that a several properties in the EST trial got a COP of 1.6 or less.

The trouble is you have absolutely no guarantee of performance of the system, you are taking pot luck.

If you are lucky and get an overall COP of 3.0 you will be getting heat at a cost of 4p/kWh. So 3p/kWh cheaper than oil.

However as pointed out many times in posts, and conceded by the EST, you need to take into account that an ASHP needs to run virtually constantly to be effective. If the house is unoccupied during the day, you can have oil/gas CH switched off and have it timed to come on, say, 20 minutes before you return and CH water at up to 80C in radiators will quickly bring the house up to heat. The same at night, although you can set back the temperature, the ASHP will be running for some of the time if you want to get up to a warm house.

The point being that an ASHP will be producing heat when, in many cases, it is simply not required as the house is empty, or you are in bed. Thus, say, 15,000kWh heat from a oil/gas boiler is more effective than 15,000kWh from an ASHP.

The difficulty is quantifying how much of that heat is 'wasted' - naturally the manufacturers won't enter discussions of that aspect; and the EST just concede the principle. To be fair the 'waste' will depend on individual circumstances.

The next thing to consider is how much this 3p/kW with a COP of 3.0 will save you in a year. If 15,000 kWh is a ballpark figure, you will save £450pa - ignoring any 'wasted' heat.

The extra outlay of £2,500 for an ASHP over a new oil boiler means you would break even in about 6 years - assuming you didn't have to borrow the £2,500.

IMO at £11k for an ASHP it would be a complete non-starter.

Not a straightforward decision I fear, and a post that will nark some ASHP enthusiasts.

andytanner

Very kind - thank you

Interestingly it was the price of the combi oil boiler that drove me to look at another solution.

The new oil boiler itself is £3k (Worcester Bosch) and I was getting no where on getting a better price for a quality product. Add in installation and commissioning and you are pushing £3.5K

The numbers for the ASHP also mean I will get £850 back from the Government (and £150 top up from Samsung - I think). Also there are the RHI (Renewable Heat Incentive) payments that are being proposed with 20 years worth being paid over 7 years. Calculated by the MCS installer at more than 6ppKwh (but not yet finalised) being paid on calculation of the heat moved across. I am not sure but it should be at least a couple of hundred a year. To balance the COP over the year they have to run the calculation anyway. For the avoidance of doubt this does not mean 6p * 24 hours *365 days * nominal heat loss (7Kw in my case) as the system is not running full power all the time.

Maintenance seems broadly the same - you should service Oil annually and the Heat Pump Unit and Cylinder require the same

What makes it even more complicated to work out returns is some of the more private conversations with installers. The life of the monosource block is nearer 10 years not 20. The last Oil boiler lasted over 20 years. That said they are only going to come down in price and the technology allows very easy replacement as you are just replacing a unit that is generating hot water and controlling the valves and immersion.

That said, the return over replacing the oil boiler with ASHP should (!?) be massively cheaper than replacing with oil again and you get to do "the right thing". Always keen to do that especially when the balance sheet is the right way round to do it

nande2000

andytanner wrote: »

What makes it even more complicated to work out returns is some of the more private conversations with installers. The life of the monosource block is nearer 10 years not 20. The last Oil boiler lasted over 20 years. That said they are only going to come down in price and the technology allows very easy replacement as you are just replacing a unit that is generating hot water and controlling the valves and immersion.

When I was pricing an external condensing oil boiler a few installers told me that there were no end of problems with them. True Worcester will give you a good warranty and the parts supply chain is seconds to none; They all agreed a modern condensing oil boiler has a lifespan of 10-12 years. Petrochemical industry analysts all agree that the price of oil will double in 10 years and double in ten years after that, though there is an outside chance that liquid biofuels may be a reality in say 15 - 20 years.

Have you spoken to IceEnergy ? I almost went with them. If you get a local plumber to do the install and Ice do the supply and comissioning it worked out quite reasonable and you get a proper design for your new system too - a note of caution though, they admitted to me they were oversizing by half a kw.

Cardew

andytanner wrote: »

Very kind - thank you

Interestingly it was the price of the combi oil boiler that drove me to look at another solution.

The new oil boiler itself is £3k (Worcester Bosch) and I was getting no where on getting a better price for a quality product. Add in installation and commissioning and you are pushing £3.5K

Well you drove a hard bargain with the ASHP installers.

Can you not get a Worcester Oil Combi cheaper than £3k?

There are a number here at under £2k

http://www.discountedheating.co.uk/index.php?route=product/search&filter_name=worcester%20oil%20combi%20boilers

dullnote

Hi just thought I would put my comment in. Cardew. I know from reading here you are against ASHP, I have installed one in my house and I think it is great. But you do make good comment it is not for everyone lifestyle or house.

I have a new house two years old, high insulation and underfloor heating, I work from the house so want house warm all day.

Companies selling ASHP should point out it is slow to heat and should not be compared with a boiler, the temperatures are much lower, mines runs at 35 degrees. Also if your house has draughts forget about ASHP.

In short ASHP in correct house where occupants know the difference between boiler and ASHP, these are good, the industry does itself no favour trying to put these in all over the place, poor reputation travels fast

So Andy, look at your house and your lifestyle before you make your mind up.

Dullnote

andytanner

Thanks Dullnote.

As a background to our lifestyle.

I work 5 days a week and while I am out during the weekdays in my current role, most roles I have are based from home. My Partner works from home in her career so the house is broadly heated all day every day. We don't run the house hot (about 19 degrees) and now I have gone round and realigned and resealed all windows and the UPVC doors there is not a draught to be found. Insulating the walls seemed to have helped enormously with that as well.

I do have a degree of nervousness about attempting this in an old house, but our oil usage dropped hugely when we went around and did all the obvious heat retention strategies. The problem we have now is that during the winter we need more ventilation than we have with the house buttoned up. Getting ventilation without throwing energy away by opening windows / doors is going to take MHRV (Heat recovery ventilation). Or in English - MORE capital expenditure. Anyone know if MHRV qualifies for RHI?

I can understand now why people just soldier on with old technology and don't bother changing. I do hope the RHI subsidy pushes more people to make the change though. Definitely worth it.


Environmental Balance

I did want to make a quick note about power consumption in ASHP just being energy burnt elsewhere. That is not strictly true and is an oversimplification.

Having been involved in Utilities / OFGEM and understanding industry settlement in painful detail, there are huge spikes in cost (to the suppliers) of electricity about times of large consumption (mornings and evenings). At other times where baseload (nuclear, wind, tidal) that is generating for free (incrementally speaking) the cost is very low. It also has a much higher mix of non fossil fuel at these times as baseload is normally used before burning fuels (incrementally expensive)

We also have utilities chewing over gearing up for true half hour billing (variable tariff by time of day) in domestic supplies. UKPN (London and South East) and WPD (South West / Wales / Midlands) have run already run trials on this technology. Given that the true peaks only last a few hours morning and evening, you could program your ASHP to shut down in the peaks and just use much lower cost power at non peak times.

In this scenario everyone wins. The consumer gets a better price, the peak loading reduces which helps reduce capacity requirements (which are expensive to provide) and reduces fossil fuel usage. It also reduces the need for standby generation and reduces the use of energy storage technologies (like pumped water / turbine storage systems). All of these factors reduce the cost of power and distribution network provision to everyone. It also supports a higher mix of wind/wave/solar as part of the energy mix.

Apologies for being a bit techy - didn't mean to be, just wanted to inform the argument.

Andy

Cardew

dullnote wrote: »

Hi just thought I would put my comment in. Cardew. I know from reading here you are against ASHP, I have installed one in my house and I think it is great. But you do make good comment it is not for everyone lifestyle or house.

I have a new house two years old, high insulation and underfloor heating, I work from the house so want house warm all day.

Companies selling ASHP should point out it is slow to heat and should not be compared with a boiler, the temperatures are much lower, mines runs at 35 degrees. Also if your house has draughts forget about ASHP.

In short ASHP in correct house where occupants know the difference between boiler and ASHP, these are good, the industry does itself no favour trying to put these in all over the place, poor reputation travels fast

So Andy, look at your house and your lifestyle before you make your mind up.

Dullnote

Totally agree with your post, except the comment about being against ASHPs - I own a system abroad.

The trouble is that there is little balance in threads which are followed by enthusiasts and those in the trade.

You simply cannot ignore the results of the EST trial and all over the web where people(often tenants) are highly unsatisfied with their systems.

as I have said many times, you shouldn't be put in a position of spending well over £10,000 and take pot luck that your system will work OK.

Of course the technology works, but the industry should get higher standards and ensure systems work!