Boiler change!!

[pip1954]

I been watching this with Boris, we have all got change our boilers to air source just wondered what people's views were .
I have seen these used on large ponds but they have problems in the winter when we ! would need them.

 

[Stigmorgan]

They work basically the same as refrigerator, I'm not 100% convinced the technology is up to scratch yet but will find out soon enough with work/school having to change from oil fired heating to air source soon, I believe the current plan is for gas boilers to be stopped on new builds from 2025 and then from 2030 or 2035 you won't be able to replace a gas boiler.

 

[Fitzroy]

Technology has been around for ages, it's the same as the air conditioning units used all over the world. Two main challenges are.
- They are c. 300% efficient, this mean you get 3x the heat out as the electrical power put in. Gas is roughly 1/3 the price of electricity so there is no yearly cost saving.
- The central heating outlet temperature is c. 40degC, compared to c.65degC on a current system. This means you need more radiator area for effective heating, they are great paired with underfloor heating.

As you likely need more radiators, or a conversation to U/F heating, the total install/conversion cost is high and with zero yearly cost offset it's an expensive proposition. The advantage of moving all our heating/transportation infrastructure to electric is that as the carbon intensity of electricity drops this is instantly passed to every home and vehicle.

I think the hope is that as we grow electricity from other non hydrocarbon sources and reduce gas and oil production the relative cost of electricity to gas drops and there becomes an economic argument for most consumers to swap.

Personally I think ground source is the way to go but install costs/disruption are horrid!

Fitz.

 

[Spectric]

I been watching this with Boris, we have all got change our boilers to air source j

And you believe a word he say's ! The problem is being looked at from the wrong perspective in that we build a house and then look at heating it, we need to build houses as homes and not just for profit which means having much thicker walls with more insulation and homes spaced out and not cramed into a space so as to maximise returns for shareholders. Rather than looking at ways to heat the home lets build homes that need very little heating. This will work both ways because then they will also be much cooler and so will not need aircon when our summer temps go past 45° C which is where they are heading as we do nothing to slow down global warming. If you look at the recent house fires and then look at a modern housing estate it is obvious if one catches fire then most of the estate will also burn, a lesson from the great fire of London due to proximity of houses.

 

[Phil Pascoe]

we need to build houses as homes and not just for profit which means having much thicker walls with more insulation ...

My cousin's was built 10 - 12 years ago with 300mm cavity wall insulation. It costs next to nothing to heat.

 

[Richard_C]

I went through a lot of thinking and investigating before replacing our 35 year old oil boiler last year. No gas in this village. I ended up with a new much more efficient oil boiler and much better controls, got the best 'blueflame' technology available at the time. I reckon last winter we used much less oil - you never can tell because winters vary - but maybe 25% saving, a bit via boiler efficiency and a lot via better controls.

So why not ASHP? The reasons others have alluded to: the temperature differential (radiator to air) is much less so you need to have bigger radiators - disruption in every room inclusing major layout changes - and/or an always on system> The house isn't terrible but to make it work I would have needed much better windows and insulation so the total cost would have been 2 or 3 x the ASHP cost, and a general worry about being wholly dependent on electricity for heating - with oil I do have some choice about when and where I buy it. There is also the curiousity that ASHP is less efficient (input vs output) in the coldest weather. So on balance, and with some guilt, I didn't do it.

A smaller house, new build and/or higher insulation standards and certainly if designed in and installed from day 1 it should be a clear ASHP (or ideally GSHP) choice, but for most of us we have to balance environmental responsibility with financial reality. I couldn't afford to do the job properly.

I have seen some hybrid systems, essentially ASHP for most of it and an in series oil or gas boiler and a brain which tells the system which to use. That might help in older properties, but the very good engineer who came to quote and do the job (known him years, not an "energy consultant") shook his head and said that I would be paying lots for ASHP but the boiler would still run a lot of the time.

A few ski resorts built in the 1960's, like Flaine in France, and most urban housing in former eastern bloc countries, have a centrat boiler house or two. You don't buy gas or electricity, you buy heat. That strikes me as a way to go for dense housing - the operator can use the most efficient technology and update it as required, even having multiple technologies and using the one that makes most sense 'on the day'. Power and fuel distribution gets a lot easier too.

Truth is, the people that live in the least efficient draughty damp houses where ASHP woudl make a real difference can't afford to do anything about it. Some can't even afford LED lightbulbs even though they repay themselves in just a few winter months.

(Listening to Johnson though gives me an idea. Maybe I should go that route - I will give Lord Brownlow a call and see if he will stump up a few £££ to install and a few ££££ for new wallpaper afterwards.)

 

[Lorenzl]

it's the same as the air conditioning units

That is part of the problem; not very much research has gone into improving them. We did a project at work for a company looking to build ASHP's from scratch and the possible improvements were great.

I can still remember the government's compact fluorescent debacle and worry ASHP's are going the same way.

We are soon moving into an old house that needs renovating and are going for an electric boiler and might add a Sunamp thermal store later. I did consider oil but it has problems with storage and supply - although the bigger the tank the easier the supply. Can fill at cheaper times of the year.

 

[Jameshow]

I been watching this with Boris, we have all got change our boilers to air source just wondered what people's views were .
I have seen these used on large ponds but they have problems in the winter when we ! would need them.

Large ponds???

 

[mikej460]

ASHP or GSHP will only work efficiently if your house is very, very well insulated and your radiators and/or underfloor heating are sized correctly. Otherwise you will be paying out a huge premium for a larger system than you need and it will be working far harder to keep you warm. Insulation is key and for older houses this could result in huge disruption and cost to dry line every external facing internal wall, double/triple glazing, floor insulation and more obviously maximum loft insulation.

 

[Lorenzl]

Obviously there is a diminishing return on insulation; from a green house forum:

No it's not linear. Say 50mm halves the heat loss and the heat loss is 10W. If 50mm insulation halves it, then you're now losing 5W. If you add another 50mm and that halves the heat loss again, you're now losing 2.5W. So that first 50mm cut your loss by 5W, but the second 50mm only cut it by 2.5W. If you halve the heat loss again, you'll need to double the thickness of insulation, so 100mm will only save you 1.25W and so on.

This also when insulation prices are going up so it is costing you a lot more for less effect.

 

[Terry - Somerset]

On the continent the typical room aircon unit will blow either cool or hot air. So I don't understand the need to upgrade radiators or install underfloor heating to deal with the lower temperature output.

Or is the issue that an ASHP will work at a higher efficiency than the above mentioned aircon units.

Using aircon units means that the fans are at high level releasing wall space, allows all central heating radiators to be removed, installation is possibly more straightforward than conventional radiators.

 

[Spectric]

On the continent the typical room aircon unit will blow either cool or hot air. So I don't understand the need to upgrade radiators or install underfloor heating to deal with the lower temperature output.

A heating system will have a flow temperature, this was as high as 80° C before condensing boilers with a return around 20°C lower, with condensing boilers this has been reduced to 60° C in order to get the return temperature low enough to allow the boiler to condense and it is this flow temperature that is used to size your radiators so as to get a temperature differential across the rad of around 12° C. If you reduce the flow temperature then that radiator will output less heat unless you fit a larger radiator to compensate for the lower flow temperature. Underfloor heating uses a much lower flow temperature than a radiator so is better suited to heat source systems.

 

[eribaMotters]

I should be able to report back in a years time on how good heat pumps are.
We move in September to a new build bungalow which has the latest generation Samsung heat pump. I've seen reports that these now have an efficiency rating of over 450%, so savings are a reality and not a break even issue.
A new build is ideal for this type of heat source, as it does not use radiators. We will have zoned underfloor heating in a screed over a heavily insulated concrete block and beam floor. 100mm wall insulation and 400mm roof insulation will help things along. I believe the EPC rating is 89.
I have heard reports of the hot water on some systems not being as hot as owners would wish, but the unit works at 60c + once a week or on demand for the hot water. I've also discovered the insulation on the hot water tank is so effective they claim a heat drop of less than 0.3 degree per hour.
Hopefully happy days lie ahead and we will not be so badly hit by rising energy costs, but time will tell.

Colin

 

[Just4Fun]

We installed a GSHP in around 2007. All we did was put the heat pump in the existing heating system. We didn't change any radiators. We didn't improve any insulation and the house dates from the 1890s so is probably not well-insulated by current standards. Our winters are colder than the UK. Despite all this our system works well, so I would think it would also work well in the UK. So why are heat pumps so rare in the UK?
UK has worst heat pump sales record in Europe

 

[D_W]

ASHPs are generally forced air here. They work fine, but are usually installed where forced air is already in place.

GSHP has also become popular here and a gaggle of my relatives (where you would heat with oil - and in cold places) have also had it installed at a cost of around $20k (bigger than the average UK house, but not huge - figure 3k SF heated, but with the potential to have winter temperatures below -20C from time to time.

None have had any increase in bills. In one case, a somewhat newer house that's got cast iron baseboard heating now just has the baseboards sitting unused. Ducting was installed between walls with flexible tube, which was less eventful than expected.

Both had the same GSHP installed and both had a control board failure (the bigger units have a whole bunch of control boards) that didn't hinder the units from working, just took some customizing options away temporarily, and both were fixed under warranty. A third with no such issue.

The only complaint I've heard from all three is they were all used to propane or oil fired water heating via coil and the environmentally friendly water heaters attached to GSHP are large, but slow to recover. AS in, if someone goes through 100 gallons of water for laundry and consecutive showers, nobody will have hot water for a few hours. the solution was to piggy back another tank with the water heater so that there is so much hot water in reserve that the standby supply will never run out.

Cost savings are so significant vs. oil here (plus a tax credit for 1/3rd of the system) that payback with interest is had within less than a decade).

 

[Bingy man]

As a gas engineer of 30 years + ground source heat pumps also air source pumps are not new but 10-15 years back when I first heard of them the cost to install was horrendous but you all need to remember that in 2015 (I think) told you to change your old inefficient boiler for the latest condensing boiler . Indeed many of you may have received a 100% grant if you met the criteria, others may have been set up with what was called “ the green deal . Along with grants for loft insulation and cavity wall insulation/ external insulation. So if you have done this and your boiler is up to date then you are fine as you are . If your boiler is d rated or lower then you need to have an a rated condensing boiler fitted . This will give you 15 Years of efficient heating. Gas is no longer guaranteed on new build homes as the move to sustainable energy is the government’s preference. Also many properties are not suitable for air or ground source pumps so what then . My apologies for not reading all the above posts cos I’ve been in a/e all day with severe abdominal pains. Prior to 2015 we advise thousands of customers with back boiler/ fire units to change it prior to the 2015 deadline or they would have to convert the system to a condensing boiler .so I would assume the same applies to any deadline to have a heat pump of any type . Eventually there will be no natural gas left but I’ve been hearing this for years. pre 1977 ish we converted from town gas to natural gas and hundreds of thousands of appliances were classed as unsuitable for conversion and thousands more never worked properly after the conversion- so personally I would tell boris to do one and stop lying to fleece the hard working cash strapped people of the uk . Keep your air / ground heat pumps along with the electric vehicles the average person can’t afford -rant over …

 

[PhilipL]

Elderly friend got a quote for a heat pump a few weeks ago for his bungalow. £20k they told him. New radiators seem to have been required. He would never get his money back at that price.

 

[Bingy man]

Elderly friend got a quote for a heat pump a few weeks ago for his bungalow. £20k they told him. New radiators seem to have been required. He would never get his money back at that price.

Exactly my point- how many of us got that kind of money-2 or 3 grand for a new condensing boiler is difficult enough but another 17k on top is just crazy.

 

[KeenToLearn]

Approx 20 years ago, my parents fitted evacuated tubes for water heating, saved a lot of money.

Prob about 10 years ago installed solar panels under FITS scheme and saved even more.

Then a year or 2 after, removed old their gas boiler and installed an air heat pump (at the time govt were intimating they would introduce a scheme like FITS for them and salesman convinced my dad it would happen and be backdated....)- bills shot right up. In the end 5 years ago, parents had had enough, took out air pump system which was sold for spares and installed new gas boiler. They are now warmer and bills went back to what they once were. A costly mistake they wish they had never made. They may be suitable for heavily insulated new builds but certainly not for older properties!!!

 

[The Chiller]

Very interesting read. Thank you Bingy Man I totally agree.