Heat pump advice

matelodave

shinytop said:

chris1973 said:

Stayed in a Airbnb during the beast from the east a few years ago, in a property heated by a ASHP. It was the coldest, most unpleasant experience of my life. Ok, it was a typical 1940's built property with just the usual double glazing , loft & cavity wall insulation etc, but so is mine and probably millions of other houses in the UK.

Unless you live in a massively insulated new build built to a plethora of Tree Hugging  EU approvals then don't bother, certainly they aren't suitable for older houses with average levels of insulation, or a stone cottage built in 1910!.

The radiators on the system I used are tiny, and barely get aired to the touch, and I don't think the system produced water temp above 47c degrees during my entire stay, in fact during the coldest night (-11c granted) the whole system shut down, flashing an 'E' number, and the owner told me it was probably too cold outside and the system had iced up!. Absolutely pointless if you can't even get aired radiators on the coldest nights of the Winter!.

I met the owner when I handed back the keys, and he admitted he had received a lot of complaints from guests about hot water not hot enough to wash dishes, and being cold during their stay because the radiators and UFH just wasn't up to the job. He even said he was no longer taking bookings during November - March because his Electricity bill was huge from having to run immersion heater back up to make the hot water hotter, and running Electric Heaters. 

Apparently the system (he had) also runs a immersion heater cycle to 65c every week burning off  even more expensive Electricity to complete a Legionella cycle. I suspect if the water this hot rocking system is producing won't even kill a bit of bacteria, its not going to be the most effective way to output heat into your home.

The Airbnb owner said that the system also has to be set to run 24/7 in order to build up and maintain any levels of background heat and heat the fabric of the building. Not sure what is 'Green' about running your heating 24/7. I run my GCH for around 6 or 7 hours a day in Winter, running 24/7 to warm the same building to the same level seems counter productive to me, if we are really saving the planet............course we are.

If you can't get a phone signal inside your new house, then you probably have internal insulation to the level where ASHP will be effective.......maybe. For people in older properties with only average levels of insulation, I seriously doubt that you will find it a direct like for like alternative for gas. But very good luck with that!.

Most of this is complete nonsense btw. 

Agree with ShinyTop - chris1973 is talking a load of cobblers and doesn't know what he's talking about and is just regurgitating hearsay.

Trying to run a heatpump like a gas boiler will certainly cost a lot more and give less satisfaction than actually owning one and knowing how to use it properly. It is quite a bit different from renting a place for a week or a fornight and not having a clue.

wittynamegoeshere

Lewigreg081281 said:

Our annual usage on gas Sep 20 to Sep 21 was 35965 so the £402.84 annual cost is way out from Zebra. Our boiler is probably around 10-15 year old and was in before we moved in so it won’t be great. 

You should be able to look up the make and model and find out its efficiency figure.  I'd expect it to be pretty good if it's only 10-15 years old - it should be a "condensing" one, and many people have boilers that are much older than this.

Has it ever been serviced?  This could make a night vs day difference if it's not been touched for a few years.  It's not rocket science, the main thing is that they literally hoover out all the dust that will be clogging up the burners.  I've seen the inside of my old one that wasn't done for just 3 years and it was filthy.

If the flames are orange rather than blue then you might need to spend around £100 solving the problem rather than £1000s on chucking everything away and starting again.

Reed_Richards

chris1973 said:

Stayed in a Airbnb during the beast from the east a few years ago, in a property heated by a ASHP. It was the coldest, most unpleasant experience of my life. ...

The radiators on the system I used are tiny, and barely get aired to the touch, and I don't think the system produced water temp above 47c degrees during my entire stay...

If you talk about the fact that you are considering a heat pump, the chances are you will find someone who has had a bad experience with one.  In this instance it seems likely that a heat pump was installed as a replacement for some other type of boiler without changing the radiators.  If you want to get the RHI you need to use an MCS accredited installer who is required to perform a detailed heat loss evaluation of your house and make sure you have radiators that are up to the job of running at a temperature of around 47 C and still providing the heat required.

BUFF

wittynamegoeshere said:

Lewigreg081281 said:

Our annual usage on gas Sep 20 to Sep 21 was 35965 so the £402.84 annual cost is way out from Zebra. Our boiler is probably around 10-15 year old and was in before we moved in so it won’t be great. 

You should be able to look up the make and model and find out its efficiency figure.  I'd expect it to be pretty good if it's only 10-15 years old - it should be a "condensing" one, and many people have boilers that are much older than this.

Has it ever been serviced?  This could make a night vs day difference if it's not been touched for a few years. 

& if it is a condensing boiler is it actually set up  to run in condensing mode most/all of the time (many are not)?
What are the controls like - these can make a surprising difference?

The first thing to do imo is to insulate/draught proof etc. to get the heat requirement down & optimise the running of what you currently have.

Rodders53

Lewigreg081281 said:

 we’d then spend a fortune on new insulation, windows, 

THIS ^^^^^^ is the first thing to spend money on!  It'll save energy from whatever source you use to heat the home.

In any case I thought the house insulation needs bringing up to standard in order to receive RHI payments?  (Loft and cavity wall insulation in particular).  Maybe they've included some of that in the costs provided so far - or will add the cost on when they do the report proper for £150?

lohr500

As per other comments above, if it was me I would be considering the following : 

1. Improve the insulation and draft proofing to reduce the heat losses and reduce gas consumption.
2. Consider adding thermostatic radiator valves to facilitate room by room temperature control.
3. Establish the make and model of the existing boiler, then check on its theoretical efficiency here : https://www.ncm-pcdb.org.uk/sap/pcdbsearch.jsp?pid=26
4. If the central heating/hot water system has gravity fed hot water circulation, look to get it converted to a valve controlled configuration so the heating and hot water can operate independently.

If it is an older boiler with a theoretical efficiency well below 90% , then I would seriously consider replacing it with a new gas boiler. The actual efficiency of the old boiler is probably going to be below the theoretical level unless it has been well serviced and set up. Yes, it does take careful set up and balancing to get a modern condensing boiler to operate at maximum efficiency, but this isn't difficult. 

1 and 2 can be done relatively cheaply. 3 and 4 will be more expensive.

In my case we had a 35 year old 100,000 btu oil boiler with a gravity fed hot water system and no valve control for either the hot water or central heating circuit. The boiler theoretical efficiency was 70%.

I had the boiler replaced with an equivalent output modern condensing oil boiler, with a claimed efficiency of 92%. Whilst they were installing the boiler, they also converted the system to valve control with a separate thermostat on the immersion tank to control the boiler.

Through careful monitoring of our oil consumption using an in line oil flow meter, I calculate we are using 30% less oil than before, with no reduction in the times of day that the central heating runs or lowering of the main thermostat. 

The old boiler was on its last legs and it was proving increasingly difficult to get spare parts for, so a change was needed.
I looked at ASHP, but the financial numbers just didn't make it viable for our old farmhouse property.

Be aware also that if you do get the RHI grant, it stays with the house, not you. So if you decide to sell your house and move, the grant passes to whoever buys your house.

addled

Are heat pumps any good? Yes.

Would I replace an existing  gas boiler with a heat pump?  Probably not but it would depend on the level of insulation, my usage scenario and the existing plumbing.

I had a heat pump system installed 7 years ago and have no regrets.  This kind of gentle heat is very comfortable.  The system is designed to run 24/7 during the colder months.  This in a small detached house, partly stone built c1800 (cold damp walls!).

 

The RHI figures are based on 'heat demand' ie heat loss.  You won't get an accurate figure without a proper survey. Installers are likely to be guessing based on a best case scenario (mine did).  If you qualify the RHI payments are straightforward.

I paid around £10.5k with 4.5k RHI grant giving a cost of around £6k all in for a complete system.   I also have solar PV but I think any crossover benefits are likely to be overstated. 

Good experience here with Mitsubishi hardware and support.  Nothing to compare with but running costs seem very reasonable so far at around £4-500 pa total energy bill (obviously more going forward). 

Points to take into consideration.  
Extra radiators are required as well as a new unvented hot water cylinder which is considerably larger than a conventional hw tank.
Heat pumps can struggle in very cold + damp conditions.  Some secondary heating is advisable, I have a wood burner, though not often used.
If you only need heat for a few hours a day this is probably not for you.
Choose your installer carefully as they need to know what they're doing and you may need them later.
An annual service costs around £150.
The cost of heat pumps may come down (or it may not).

Lewigreg081281

Thanks all. 

Are there any grants for insulation at all? I’ve got all sorts of ads flying up on Fb now due to me talking and posting about it 😂

how much does it cost for an average loft insulation? We have some foil type thick sheets all over the loft roof. I’m not sure what’s behind that though. We’ve just lived with it Like that over the years. 

Any other tips for making the home more efficient. I’ve seen the foil radiators sheets and draft tape you can put inside windows and doors. Not sure how successful these will be. 

Thanks all

QrizB

Lewigreg081281 said:

How much does it cost for an average loft insulation? We have some foil type thick sheets all over the loft roof. I’m not sure what’s behind that though. We’ve just lived with it Like that over the years.

Basic loft insulation is pretty cheap, eg:

https://www.diy.com/departments/knauf-eko-roll-loft-insulation-roll-l-4-83m-w-1-14m-t-200mm/182147_BQ.prd

£25 for a roll but three for £18 each in the current offer. Whether it's worth doing will depend on what you've already got in the loft.

JudgeDekker

I'm on oil, and my system works and the radiators are lovely and toasty. I did the maths, and I could maybe make a decent saving over the seven year period. But not nearly enough to be worth the hassle and risk of ripping it out and putting it an ASHP.