Heat Pump in 77 Dallinger Road
With climate change an ever-greater threat in our lives I wanted to share our experience of changing our heating system in our home, to remove our direct emissions of Carbon Dioxide, and therefore contribute to the national effort to move to Net Zero.
Until July 2023 like most people we had a fossil fuel Combi Gas boiler powering our central heating. Fossil fuel gas is cheap and convenient, but our combi boiler and front room gas fire was producing some 2.2 tonnes of CO2 emissions each year, roughly the equivalent emissions as 8 return flights to Spain. In the past the only alternative form of heating, which is emissions free at point of use, was electricity but the unit cost at some 3 to 4 times more expensive than gas made any change unrealistic.
The Heat Pump
So, enter the Heat Pump, A Heat Pump essentially works exactly like a domestic fridge. It extracts heat from the ambient air outside your house and transfers it to the inside, just like your fridge does from inside the fridge to the kitchen.
In our case the Pump transfers the heat to the existing central heating system to replace the need for a Gas Boiler.
The Heat Pump we have installed looks like this on our patio – not exactly an aesthetic enhancement ! but something we can live with. The pump when running makes a low hum but is actually remarkably quiet compared to many air con type units you may have had experience of. Apart from 20mins at night for hot water, the pump only operates in the winter and so is not operating whenever its warm enough to sit in the garden. Even when it is operating then it does so mostly at its lowest power mode so we really don’t notice it in our daily lives.
The Heat Pump is powered by electricity, but its big advantage is that it can transfer some 3 to 4 times as much heat as it uses in electricity effectively making it much cheaper to run than traditional electric heating.
The pump has insulated pipes which transfer heat to a system inside the house which then transfers it to the Hot Water tank and Central Heating system. One disadvantage of this system over a Combi Gas boiler, is the need to have a Hot Water tank for the house which obviously takes up space. We have created a new cupboard in one of the bedrooms to house it. The previous combi boiler has now been removed creating a new cupboard in our bathroom.
Radiators
One of the big decisions of putting in such a pump is – do I need to change the radiators? Early Heat pump systems could only operate at low temperatures necessitating larger than usual radiators to effectively heat a house. That is no longer the case. Most modern Heat Pumps can happily generate output flow temperatures up to 60 degrees which is the equivalent of most Combi boilers. Our front room radiator was a bit undersized according to various installers, but we decided not to replace it and have a top up Electric Fire for that room only. Consequently, we are now running the system on exactly the same radiator circuit as before.
House Insulation
The received wisdom of Home Energy improvements is that improved insulation should come first and is essential to the comfortable switch to use a Heat Pump. Our experience is that that is true but only to a point. Our house already had a Loft Extension so was already well insulated at the top of the house. We did improve some insulation and our calculations suggest that where that can be done by fitting internal loft insulation, double glazing windows and preventing drafts then that is a better first use of any money to improve your energy efficiency. Beyond that the next step was External Wall Insulation (EWI) to compensate for the lack of an internal wall cavity in our 1920’s built home. I had looked at EWI in the past but was always put off by the cost and long payback. We decided to compromise and have fitted EWI to both the front and side of the house but not the back where the external drainage pipes would make it more expensive to install.
My rough calculations have estimated that the EWI we have installed is saving us some 1/3 of our total heating bill going forward and so we can expect it to pay for itself over a 25-35 year period. It does however make the house more comfortable to live in – it essentially stays warmer for longer inside when the weather turns cold and stays cooler when the weather gets hot.
Our experience is that the EWI is a nice to have but not an essential addition to the switch to using a Heat Pump. Having the EWI means the Heat Pump doesn’t have to work quite so hard in the coldest winter months, but it would have been quite capable of doing so were that necessary. Also, the EWI means that we can run the heating for much of the time at a lower flow temperature which makes it more efficient and cheaper but the difference is not large.
House Insulation
The received wisdom of Home Energy improvements is that improved insulation should come first and is essential to the comfortable switch to use a Heat Pump. Our experience is that that is true but only to a point. Our house already had a Loft Extension so was already well insulated at the top of the house. We did improve some insulation and our calculations suggest that where that can be done by fitting internal loft insulation, double glazing windows and preventing drafts then that is a better first use of any money to improve your energy efficiency.
I had looked at EWI in the past but was always put off by the cost and long payback. We decided to compromise and have fitted EWI to both the front and side of the house but not the back where the external drainage pipes would make it more expensive to install.
My rough calculations have estimated that the EWI we have installed is saving us some 1/3 of our total heating bill going forward and so we can expect it to pay for itself over a 25-35 year period.
It does however make the house more comfortable to live in – it essentially stays warmer for longer inside when the weather turns cold and stays cooler when the weather gets hot.
Cost
Installing the Heat Pump including the new cupboard inside has cost us about £9,000. This was after being reduced by the Government Grant of, in our case £5,000. This grant has now been increased to £7,500. The External Wall Insulation cost £13,000.
The running costs of the Heat Pump are roughly the same as a Gas Combi boiler on a standard electricity tariff, the extra cost of the electricity compared to gas is basically countered by the efficiency of the pump. However having the pump has allowed us to switch to a time of use tariff with Octopus which allows the Heat Pump to operate most of the time at ½ price electricity. This along with saving the Standing Charge of Gas at about £120 pa is making the Pump considerably cheaper to operate than Gas.
Thus far this year 01Jan-30Apr 2024 our energy costs for the Heat Pump have been £361
Conclusion
So enhancing our home to make it Carbon Neutral has cost some £22,000 a figure which will be largely repaid over some 25 to 35 years in reduced bills. Not a huge investment in the house given it represents less than 3% of its estimated value.
Save £7,500 with the
Boiler Upgrade Scheme
Up To £7,500 In Government Grants Get £7,500 towards an air source heat pump with government grants. Check your elgibility for a greener, more affordable home.
Lower
Energy Bills
Air source heat pumps are much more efficient than traditional heating methods like gas boilers. This can lead to potential savings on your energy bills in the long run.
Supreme Heating and Air Conditioning have many happy clients in and around the South London area that use us time and time again for all their plumbing & heating requirements
