Boiler change!!

[shed9]

One major lurking problem with ASHP's is fundamentally linked to the weather we are experiencing right now. According to the weather modelling from the Met Office, moving forward we are highly likely to experience a similar extreme heat wave every five years as opposed to the usual model of one in every 50. As we approach 2050, that will shift towards an extreme summer every other year. Given that an ASHP is essentially an aircon in reverse this cooling operation can currently be accessed on some models of ASHP's and over time will likely be included with most, if not all, models to capture sales as summers like this one become more typical. I know that there are some proposals, even loose legislation to disable this on ASHP's and to some extent that occurs but either manufacturers will push back or modifications will be offered.

Here's the rub; that same modelling of increased risks of extreme summers also predicts wetter but more importantly warmer winters. The shift of ASHP operation has potential to be used during two seasonal weather patterns, not just one. Consumers are lazy and most people will opt to use the aircon mode in summer months as opposed to opening windows which makes aircon less effective anyhow. That 3.6-4.5 Coefficient Of Power (COP) for ASHP is fairly moot in cost savings when the price of electric power increases and usage goes up. Sure there will be people who simply won't or can't afford to run it during summer months but the scale of actual usage is likely to incur issues and create problems we never thought of, how many lost power over the last few days because of National Grid issues?

 

[PDW125]

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.

Massive amounts of research has been done and then new heat pumps running R410a have addressed a lot of the old issues. Inverter drive pumps have replaced the old high power scroll pumps (ie the old refrigeration technology), controls with weather compensation, CoP moving from 2.5 at A7W35 to CoP of 4 at A7W50, and a host of other improvements.

the environmentally friendly water heaters attached to GSHP are large, but slow to recover.

Yes because it’s simple heat transfer calculations. Modern boilers have an output of 24-30Kw in terms of heat, an ASHP will have a maximum output normally of 12-15Kw so you have half the available heat input. In terms of heat delivered, the temperatures delivered, boilers tend to run at 65-70°C and a reasonably low flow but dump 30-40°C into the store, ASHP incrementally increase the temperature by 8-12°C per cycle so take longer to increase a tank temperature.

Elderly friend got a quote for a heat pump a few weeks ago for his bungalow. £20k they told him.

Probably from one of the same merchants that used to sell Cavity wall/solar/double glazing until the grants ran out and the gravy train stopped …

 

[Just4Fun]

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.

Various posts confirm the obvious fact that costs are significant for most (all?) of us, so it is good to have some real costs to deal with. In our case the cost of our GSHP was 13K euro back in 2007. This is of course a lot of money, at least it is to us, but it has to be seen in context. Our previous heating system used oil. There is no gas option here. Our alternatives were to get a new oil burner, to heat just with electricity, or install a wood pellet system. Renewing the oil burner would have been a lot cheaper up front but cost more to run. I didn't really trust a wood pellet system, both in terms of reliability of the fuel feed and also security and cost of supplies. Our house is larger than most (about 7800 sq ft), the lowest temperature we have seen here is -39C and our heating season is long, so heating is even more important than in the UK. For us, GSHP was a good option, but how that stacks up in the UK compared to gas is another question. Our GSHP performs well but maybe a gas boiler would be cheaper in the UK.

I don't know much about ASHP. My understanding is that they are cheaper than GSHP to install, but could cost more to run. I have heard good and bad reports about how well they work, but have no personal experience. KeenToLearn's parents' experience is not encouraging. Does anyone else have any first-hand knowledge of installation & running costs for GSHP or ASHP in the UK?

 

[Lorenzl]

how many lost power over the last few days because of National Grid issues?

Interesting; our power failed on Tuesday for a short time.

Where is all the electricity coming from to power the electric cars and heat pumps?

 

[PDW125]

Eventually there will be no natural gas left but I’ve been hearing this for years.

About 53 years was the last estimate.

 

[shed9]

Interesting; our power failed yesterday for a short time.

Where is all the electricity coming from to power the electric cars and heat pumps?

https://electricinsights.co.uk/#/homepage?&_k=dvylmp

 

[Just4Fun]

Probably from one of the same merchants that used to sell Cavity wall/solar/double glazing until the grants ran out and the gravy train stopped …

Good point. It is important to find a good supplier. We got quotes for a GSHP and the cheapest was 30K euro, which was way beyond our budget. Then we had a guy here for a different job and when chatting to him over coffee he mentioned that his company supplied and fitted GSHPs so we asked him for a quote. His approach was unique. Everyone else based the choice of equipment on the size of the house but he calculated our needs based on our records of how much oil we had used in the past winter. He quoted for a smaller heat pump, at a cost of 13K euro and as a safeguard that included putting double piping in the ground loop to support a second GSHP if his calculations proved incorrect. We went for that and the second GSHP was not needed. Because of his expertise our costs were much lower.

 

[PDW125]

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.

That isn’t strictly true - efficiency is irrelevant, and the sizing issue affects all heating systems including oil and gas boilers. A poorly designed system in a badly insulated property will use more energy in any event. An oversized ASHP will happily keep a building warm but it won’t do it cheaply. What plays into an ASHP strength is the efficiency is pretty linear across the air temperature / water temperature relationship,

 

[Lazurus]

we had an ASHP installed two years ago to replace storage heaters in the bungalow purchased. The initial cost was 19K with half paid for by government scheme. This included new rads pipes tank ASHP and all the gubbins to control it. No gas in our village and I wasnt going down the bottled gas or oil routes. We did get a quote for an oil boiler full install and it worked out the same as we actually paid for the ASHP. Bungalow is a 70`s build with wooden frame and no cavity insulation. It works very well and keeps us comfortable once you find the ideal thermostat level.
My only concern is the life of the unit, 7 years full warranty but upon speaking to an engineer who was tinkering with the ASHP at work he said average life 8 - 10 years, so time will tell. We are totally electric so lets hope we dont get any power cuts or I may have to get the BBQ out for dinner!!!

 

[mikej460]

That isn’t strictly true - efficiency is irrelevant, and the sizing issue affects all heating systems including oil and gas boilers. A poorly designed system in a badly insulated property will use more energy in any event. An oversized ASHP will happily keep a building warm but it won’t do it cheaply. What plays into an ASHP strength is the efficiency is pretty linear across the air temperature / water temperature relationship,

In this context efficiency is the required heat at least cost. We agree that sticking in an oversized heat pump with large rads and poor level of insulation isn't efficient. I wasn't commenting on the efficiency of the heat pumps themselves.

 

[pip1954]

It's good to here views on this new idea that Boris has come up with. how does gs work does it still work through rads we are lucky we have a large garden.

 

[Stevekane]

Various posts confirm the obvious fact that costs are significant for most (all?) of us, so it is good to have some real costs to deal with. In our case the cost of our GSHP was 13K euro back in 2007. This is of course a lot of money, at least it is to us, but it has to be seen in context. Our previous heating system used oil. There is no gas option here. Our alternatives were to get a new oil burner, to heat just with electricity, or install a wood pellet system. Renewing the oil burner would have been a lot cheaper up front but cost more to run. I didn't really trust a wood pellet system, both in terms of reliability of the fuel feed and also security and cost of supplies. Our house is larger than most (about 7800 sq ft), the lowest temperature we have seen here is -39C and our heating season is long, so heating is even more important than in the UK. For us, GSHP was a good option, but how that stacks up in the UK compared to gas is another question. Our GSHP performs well but maybe a gas boiler would be cheaper in the UK.

I don't know much about ASHP. My understanding is that they are cheaper than GSHP to install, but could cost more to run. I have heard good and bad reports about how well they work, but have no personal experience. KeenToLearn's parents' experience is not encouraging. Does anyone else have any first-hand knowledge of installation & running costs for GSHP or ASHP in the UK?

Hi, could you tell us what was involved in fitting the GSHP to your system, I guess it just replaced the boiler, but how did they tackle the external works, what did it involve?
Steve.

 

[Lorenzl]

what did it involve?

A lot of digging

 

[mikej460]

It's good to here views on this new idea that Boris has come up with. how does gs work does it still work through rads we are lucky we have a large garden.

The internal part of Ground Source Heat Pump systems are basically the same as Air Source or Water Source Heat Pumps, However the external part of the systems are very different, GSHP work by pumping a fluid through either:
1. A large coil buried in your harden; the largely constant temperature in the soil (typically around 10 degrees) is passed into this fluid which is compressed by the heat pump which generates the higher level of heat.
2. A pipe that runs through a very deep hole into the ground where temperatures are much higher. One of these systems has been installed in a serviced office on the outskirts of our village. The depth and relative temperature within these holes determines if you need a heat pump or just a heat exchanger type system like they use in Scandinavian countries (known as geo-thermal heating).

 

[Just4Fun]

Hi, could you tell us what was involved in fitting the GSHP to your system, I guess it just replaced the boiler, but how did they tackle the external works, what did it involve?
Steve.

The GSHP is a thing the size of a washing machine. We didn't replace the old oil burner; we added the GSHP and kept the oil burner as a back-up. There are 3 connections involved.

First, the electrical connections. Our GSHP uses a 3-phase supply. I am no electrician so can't tell you much more than that. We did have a problem initially where we kept blowing mains fuses in our fuse board. It transpired that the mains supply to our house was actually lower-rated than it was documented to be and the electric company had to put in a new feed. That fixed the problem.

The second set of connections is 2 pipes, flow and return, for the radiator system. That is essentially the same as on any gas or oil boiler, so nothing unusual there. The GSHP is just connected in to the existing pipework.

The final set of connections is the flow and return that goes to the underground pipework outside the house. We have a field out the back of the house and we had a trench dug there. Pipes were laid in that trench and then brought into the house and connected to the heat pump. We had a guy come with a JCB to dig the trench. It was a fairly major effort but I don't know how much of the total cost this accounted for. The fluid that circulates in that loop is water with an antifreeze.

Does this tell you what you want to know?

 

[PDW125]

Also remember that the glycol mix in GSHP needs replacing between 5-7 years as it degrades. It’s not a cheap job and it’s sometimes missed in the cost of ownership.

 

[John on the Wirral]

Hi, I once looked into air-sourced heat pumps and how they work. When we were kids we used to restrict the air getting out of the end of a bike pump and the air that got through was quite hot - as I see it that is the principle. So moving on, air at the ambient temperature is forced through a venturi to increase it's temperature. That seemed a great idea but what if the ambient temperature was,minus 10,the electric pump would have to work it's socks off 24/7 to attempt to get the required temperature while the leccy meter happily spins around. Then.of course,the noise factor would come in and where my potential installer intend putting it was just below my neighbours bedroom balcony window and are very light sleepers!
Ground-sourced heat pumps could be a good idea if you could dig deep enough - miners were always sweating even in the winter. Maybe we could use all our disused and environmentally unfriendly mine shafts? I would say,new builds dig a big hole while you have JCB handy.
If I have got it all wrong then please tell me as I have just installed a combi.

 

[JBaz]

The GSHP is a thing the size of a washing machine. We didn't replace the old oil burner; we added the GSHP and kept the oil burner as a back-up. There are 3 connections involved.

First, the electrical connections. Our GSHP uses a 3-phase supply. I am no electrician so can't tell you much more than that. We did have a problem initially where we kept blowing mains fuses in our fuse board. It transpired that the mains supply to our house was actually lower-rated than it was documented to be and the electric company had to put in a new feed. That fixed the problem.

The second set of connections is 2 pipes, flow and return, for the radiator system. That is essentially the same as on any gas or oil boiler, so nothing unusual there. The GSHP is just connected in to the existing pipework.

The final set of connections is the flow and return that goes to the underground pipework outside the house. We have a field out the back of the house and we had a trench dug there. Pipes were laid in that trench and then brought into the house and connected to the heat pump. We had a guy come with a JCB to dig the trench. It was a fairly major effort but I don't know how much of the total cost this accounted for. The fluid that circulates in that loop is water with an antifreeze.

Does this tell you what you want to know?

I'm intrigued.

I investigated adding a ground source heat pump to my oil-fired system a few years back. Apart from the cost (the bore-hole alone was £60/m and the various suppliers wanted it between 150m and 360m deep) the major issue was that the return water temperature to the oil boiler was higher than the output temperature of the GSHP, so the GSHP would never transfer any heat to the system.

How does yours work?

 

[Stevekane]

The GSHP is a thing the size of a washing machine. We didn't replace the old oil burner; we added the GSHP and kept the oil burner as a back-up. There are 3 connections involved.

First, the electrical connections. Our GSHP uses a 3-phase supply. I am no electrician so can't tell you much more than that. We did have a problem initially where we kept blowing mains fuses in our fuse board. It transpired that the mains supply to our house was actually lower-rated than it was documented to be and the electric company had to put in a new feed. That fixed the problem.

The second set of connections is 2 pipes, flow and return, for the radiator system. That is essentially the same as on any gas or oil boiler, so nothing unusual there. The GSHP is just connected in to the existing pipework.

The final set of connections is the flow and return that goes to the underground pipework outside the house. We have a field out the back of the house and we had a trench dug there. Pipes were laid in that trench and then brought into the house and connected to the heat pump. We had a guy come with a JCB to dig the trench. It was a fairly major effort but I don't know how much of the total cost this accounted for. The fluid that circulates in that loop is water with an antifreeze.

Does this tell you what you want to know?

Many thanks indeed for the explanation J4F so in essence quite a simple system with the technical bit being performed in the “washing machine”,,what size roughly was the trench, and did they have to go very deep? I imagine plastic water pipes being laid or perhaps a special heat conductive pipework? And please forgive my ignorance but am I right in thinking that your ground in Finland is likely to be colder that southern UK?
Steve.

 

[Ollie78]

I think the best type of boiler/ heating system is something like a wood pellet gassification type boiler or something like that. They are very efficient, no need for natural gas or hardly any electricity either.

It seems daft to use electricity for everything when the supply is proving volatile and often comes from burning fossil fuels anyway.
You can't trust stuff like the "carbon footprint" which was invented by BP in order to blame the individual for industrially created carbon emissions.

Ollie