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Introduction
I am in the process of considering having solar panels installed on my house in London. Before I commit to anything, it would be helpful to have input from those who have experience and knowledge in the field to ensure that I am not making any significant errors.
Background
My house is a two bedroom mid terraced house in east London. It would at one time have been a three bedroom house, but the third bedroom was converted to a bathroom some years ago. The bathroom is thus quite large for a bathroom and has a lovely original fireplace. The house is currently heated with a condensing gas combination boiler in the bathroom.
When I bought the house in 2014, I had some fairly substantial refurbishment done, but I could not at the time afford to have the kitchen and bathroom refurbished. Part of the refurbishment included the installation of cast iron radiators. It was otherwise refurbished to resemble, so far as is practical in modern times, the interior style and finish of the 1900s. I plan to extend this aesthetic to the kitchen and bathroom.
The time has now come for me to refurbish the bathroom. Part of that refurbishment involves replacing the boiler. Since gas heating does not have a long-term future, I wish to use an alternative heating system, but retaining the existing radiators. There is insufficient space in my garden for a ground source heat pump, but there is enough space for an air source heat pump of the air to water type.
For the last 2 or so years, I have run an experiment in which I have reduced the circuit temperature of my heating system to 58C (according to the boiler's thermometer). I have found this adequate for heating the house over that time, including in quite cold weather. I have been advised that, in those circumstances, a 11kW heat air source heat pump with a working temperature of 55C will suffice for heating my house.
As is common in houses of this age and type, the house has two parts: the main part with the principal rooms (parlour, hallway, dining room, main bedrooms) and the rear addition with the kitchen (ex scullery), original lavatory and bathroom (originally the smallest bedroom). The main part of the house has loft access, boarded for storage with insulation. The back addition has no loft access and, I am fairly sure, no loft insulation. Some cracks have appeared in the bathroom ceiling (and there is also evidence of historic cracking). I consulted a surveyor last year who advised me to monitor the cracks over winter. I did this, and they appeared not to enlarge. The surveyor noted that there was no structural concern, but that I should replace the bathroom ceiling and have it tied in to the main house. I plan to do this at the same time as installing loft access and insulation.
Solar thermal
Since I am investigating heat pumps, I wish to consider solar, and, in particular, solar thermal, since, if I am having a heat pump, I will need a cylinder, and that cylinder will need to be compatible with solar thermal if I am to have that, and will all need to be connected at the same time to avoid wastage.
A particular reason for considering solar thermal is that I tend to use quite a lot of hot water for a one person household: I wash up under a hot running tap rather than in a tub of water, as I consider this more hygienic, and I like to take long (perhaps >20 minutes), hot showers in the evening just before going to bed. A solar thermal arrangement with a sufficiently large tank should be able to heat (or, at least, assist in the heating of) plenty of water during the day and store it for when I need to use it. I normally do most of my washing up after dinner in the evening.
The quote
I have only successfully been able to obtain a quote from one company, Eco Greenenergy Solutions Ltd.. Other companies that I contacted by e-mail have not responded at all. This company is MCS certified. A person from the company visited me last week to look at my house for the purposes of giving a quote.
The solar thermal component of the quote is a total of £8,300 at 0% VAT, comprising £4,900 in goods and £3,400 in installation. The specified equipment is a Veissman evacuated 12 collector tube.
The heat pump quote is for £17,850, comprising a Daikin Altherma R410-A EDLQ07CV3 11kW Ou heat pump at £10,413.00, a 300l twin coil cylinder at £3,319.00, installation, testing and commissioning at £3,200, a smart comfort controller at £350.00 and various sundries (piping, etc.) making up the rest. The installation is said to include an EPC, DNO notification and a power flush of the system.
Solar PV
When the person attended to look at my house for the purposes of providing a quote, he suggested that I also consider solar PV. The main reason that I had not been keen on this is that my electrical consumer unit is located in my hallway, and I had imagined that getting wiring to access this would have involved damaging the decor in that room, which would be difficult to reinstate as one of the paint colours is no longer available. However, the person explained that the wiring could in fact be run outside the house and over the roof, entering at the front of the hallway from the front and thereby avoiding damaging any decor. I am therefore considering solar PV also.
The original quote was for a 4.74kW peak system with panels on the east and west roofs. The panels specified were Qcell Duo ML G9 types at 395W each, with 6 panels on the east and 6 on the west roofs, with a SolaX hybrid inverter. I had also asked for a quote for battery storage, which was given as the SolaX Triple Power battery at 5.8kWh. The total quote came to £12,500 (this was not itemised) at 0% VAT. I am told that this system would have an EPS, allowing me to have backup power during a power cut.
I then inquired whether it would be possible to add further PV panels to the south roof in addition to the solar thermal panels, and what the price for the next size up in battery would be. The response was that it would indeed be possible to add further PV panels to the south roof, a total of 4 additional panels. That would bring the total cost of the PV system to £14,500 and the total system generation value to 6.32kW peak. The next size up of battery, I am told, was simply adding a second 5.8kW battery giving a total of 11.6kW, and that this would cost an additional £3,200.
Sequence of works
I had also inquired whether it would be possible to locate the equipment (cylinder, inverter, batteries) in the loft space above the bathroom. I was told that this may be possible, subject to confirmation that the joists are strong enough for the cylinder, but I should need to have the access works done first. With that in mind, I have sent e-mails seeking quotes to quite a number of builders whose details I found on the Federation of Master Builders website, but have not had a response yet. I think that I will need to start in any event with the access works.
Queries/sanity check
Despite such research as I have been able to do, I remain uncertain about a number of things. I should note that I have not made any final decisions as to what, if any, system to have installed, save that I am definitely keen to replace the gas boiler with a non-gas alternative at the time of refurbishing the bathroom and that this would be the ideal time to install solar systems.
First of all, the overall economics of solar. I suspect that this is inherently uncertain, but if anyone has any insight that is not obvious from basic research, that would be most helpful. So far as I can see, electricity prices are now very high. Gas prices are increasing and are likely to increase very considerably in the future. The economics of using solar generation rather than importing energy in the form of electricity or gas improve the higher that the price of electricity and gas are, although the complexity is at present that, for customers using the Octoupus Outgoing Agile tariff, it is more economical to burn gas for heat and export electricity than to use the electricity for heat, even via a heat pump, given that the export tariff for electricity is frequently more than 3x the import tariff for gas. I suspect that this is likely to be temporary, however, as gas prices are likely to increase.
Secondly, and related to the first, I do not know whether the quoted costs are within the range of what one would expect. I have not had success in obtaining more than this one quote or getting any other company to respond at all. This price is higher than what I have seen mentioned elsewhere, but I am aware that demand is high and that prices are increasing. If anyone can offer any insight on this pricing, I should be grateful.
Thirdly, there is the vexed question of the economics of solar thermal in particular compared with solar PV. I believe that solar thermal does have higher overall efficiency than using electricity with a heat pump, and also works better on cloudy days, meaning that it can in principle provide some pre-heating of my water even in colder months of the year (but I cannot find much in the way of information as to the real world efficacy of this). I have seen some reports of some systems being unreliable, but it is difficult to make sense of this information or make decisions on the basis of it without knowing how much that this varies between different types of equipment, how reliable that the equipment specified for me is likely to be and, in practical terms, quantitatively how much that there is in the way of reliability issues (do these systems fail every year? Two years? Ten years? Do they need maintenance more often than, for example, a gas boiler's annual inspection? How much does this vary between types?). Any insights into this would be appreciated.
Fourthly, in terms of the PV, it is difficult to know how best to size the system. The 6.32kW peak value for having panels on east, west and south facing roofs would generate plenty of electricity in the summer, but it is difficult to know in practical terms how much and how this would interact with the battery storage amount. A larger array would, of course, generate more usable amounts of electricity on less sunny days, but I do not know how much more in practical terms that this would be. Adding more panels seems less expensive than adding a further battery - but it is difficult to find good resources on ideal battery sizings, especially for a household whose heating is by way of a heat pump combined with solar thermal for hot tap hot water (DHW). This also makes it impossible for me to compute the ideal battery size based on my current usage.
Fifthly, cylinder size - it is very difficult to calculate what size that I will actually need in light of my usage, as described above. Any assistance would be appreciated.
Finally, I should be interested in anyone who has knowledge as to whether the equipment that has been specified is optimum.
I am in the process of considering having solar panels installed on my house in London. Before I commit to anything, it would be helpful to have input from those who have experience and knowledge in the field to ensure that I am not making any significant errors.
Background
My house is a two bedroom mid terraced house in east London. It would at one time have been a three bedroom house, but the third bedroom was converted to a bathroom some years ago. The bathroom is thus quite large for a bathroom and has a lovely original fireplace. The house is currently heated with a condensing gas combination boiler in the bathroom.
When I bought the house in 2014, I had some fairly substantial refurbishment done, but I could not at the time afford to have the kitchen and bathroom refurbished. Part of the refurbishment included the installation of cast iron radiators. It was otherwise refurbished to resemble, so far as is practical in modern times, the interior style and finish of the 1900s. I plan to extend this aesthetic to the kitchen and bathroom.
The time has now come for me to refurbish the bathroom. Part of that refurbishment involves replacing the boiler. Since gas heating does not have a long-term future, I wish to use an alternative heating system, but retaining the existing radiators. There is insufficient space in my garden for a ground source heat pump, but there is enough space for an air source heat pump of the air to water type.
For the last 2 or so years, I have run an experiment in which I have reduced the circuit temperature of my heating system to 58C (according to the boiler's thermometer). I have found this adequate for heating the house over that time, including in quite cold weather. I have been advised that, in those circumstances, a 11kW heat air source heat pump with a working temperature of 55C will suffice for heating my house.
As is common in houses of this age and type, the house has two parts: the main part with the principal rooms (parlour, hallway, dining room, main bedrooms) and the rear addition with the kitchen (ex scullery), original lavatory and bathroom (originally the smallest bedroom). The main part of the house has loft access, boarded for storage with insulation. The back addition has no loft access and, I am fairly sure, no loft insulation. Some cracks have appeared in the bathroom ceiling (and there is also evidence of historic cracking). I consulted a surveyor last year who advised me to monitor the cracks over winter. I did this, and they appeared not to enlarge. The surveyor noted that there was no structural concern, but that I should replace the bathroom ceiling and have it tied in to the main house. I plan to do this at the same time as installing loft access and insulation.
Solar thermal
Since I am investigating heat pumps, I wish to consider solar, and, in particular, solar thermal, since, if I am having a heat pump, I will need a cylinder, and that cylinder will need to be compatible with solar thermal if I am to have that, and will all need to be connected at the same time to avoid wastage.
A particular reason for considering solar thermal is that I tend to use quite a lot of hot water for a one person household: I wash up under a hot running tap rather than in a tub of water, as I consider this more hygienic, and I like to take long (perhaps >20 minutes), hot showers in the evening just before going to bed. A solar thermal arrangement with a sufficiently large tank should be able to heat (or, at least, assist in the heating of) plenty of water during the day and store it for when I need to use it. I normally do most of my washing up after dinner in the evening.
The quote
I have only successfully been able to obtain a quote from one company, Eco Greenenergy Solutions Ltd.. Other companies that I contacted by e-mail have not responded at all. This company is MCS certified. A person from the company visited me last week to look at my house for the purposes of giving a quote.
The solar thermal component of the quote is a total of £8,300 at 0% VAT, comprising £4,900 in goods and £3,400 in installation. The specified equipment is a Veissman evacuated 12 collector tube.
The heat pump quote is for £17,850, comprising a Daikin Altherma R410-A EDLQ07CV3 11kW Ou heat pump at £10,413.00, a 300l twin coil cylinder at £3,319.00, installation, testing and commissioning at £3,200, a smart comfort controller at £350.00 and various sundries (piping, etc.) making up the rest. The installation is said to include an EPC, DNO notification and a power flush of the system.
Solar PV
When the person attended to look at my house for the purposes of providing a quote, he suggested that I also consider solar PV. The main reason that I had not been keen on this is that my electrical consumer unit is located in my hallway, and I had imagined that getting wiring to access this would have involved damaging the decor in that room, which would be difficult to reinstate as one of the paint colours is no longer available. However, the person explained that the wiring could in fact be run outside the house and over the roof, entering at the front of the hallway from the front and thereby avoiding damaging any decor. I am therefore considering solar PV also.
The original quote was for a 4.74kW peak system with panels on the east and west roofs. The panels specified were Qcell Duo ML G9 types at 395W each, with 6 panels on the east and 6 on the west roofs, with a SolaX hybrid inverter. I had also asked for a quote for battery storage, which was given as the SolaX Triple Power battery at 5.8kWh. The total quote came to £12,500 (this was not itemised) at 0% VAT. I am told that this system would have an EPS, allowing me to have backup power during a power cut.
I then inquired whether it would be possible to add further PV panels to the south roof in addition to the solar thermal panels, and what the price for the next size up in battery would be. The response was that it would indeed be possible to add further PV panels to the south roof, a total of 4 additional panels. That would bring the total cost of the PV system to £14,500 and the total system generation value to 6.32kW peak. The next size up of battery, I am told, was simply adding a second 5.8kW battery giving a total of 11.6kW, and that this would cost an additional £3,200.
Sequence of works
I had also inquired whether it would be possible to locate the equipment (cylinder, inverter, batteries) in the loft space above the bathroom. I was told that this may be possible, subject to confirmation that the joists are strong enough for the cylinder, but I should need to have the access works done first. With that in mind, I have sent e-mails seeking quotes to quite a number of builders whose details I found on the Federation of Master Builders website, but have not had a response yet. I think that I will need to start in any event with the access works.
Queries/sanity check
Despite such research as I have been able to do, I remain uncertain about a number of things. I should note that I have not made any final decisions as to what, if any, system to have installed, save that I am definitely keen to replace the gas boiler with a non-gas alternative at the time of refurbishing the bathroom and that this would be the ideal time to install solar systems.
First of all, the overall economics of solar. I suspect that this is inherently uncertain, but if anyone has any insight that is not obvious from basic research, that would be most helpful. So far as I can see, electricity prices are now very high. Gas prices are increasing and are likely to increase very considerably in the future. The economics of using solar generation rather than importing energy in the form of electricity or gas improve the higher that the price of electricity and gas are, although the complexity is at present that, for customers using the Octoupus Outgoing Agile tariff, it is more economical to burn gas for heat and export electricity than to use the electricity for heat, even via a heat pump, given that the export tariff for electricity is frequently more than 3x the import tariff for gas. I suspect that this is likely to be temporary, however, as gas prices are likely to increase.
Secondly, and related to the first, I do not know whether the quoted costs are within the range of what one would expect. I have not had success in obtaining more than this one quote or getting any other company to respond at all. This price is higher than what I have seen mentioned elsewhere, but I am aware that demand is high and that prices are increasing. If anyone can offer any insight on this pricing, I should be grateful.
Thirdly, there is the vexed question of the economics of solar thermal in particular compared with solar PV. I believe that solar thermal does have higher overall efficiency than using electricity with a heat pump, and also works better on cloudy days, meaning that it can in principle provide some pre-heating of my water even in colder months of the year (but I cannot find much in the way of information as to the real world efficacy of this). I have seen some reports of some systems being unreliable, but it is difficult to make sense of this information or make decisions on the basis of it without knowing how much that this varies between different types of equipment, how reliable that the equipment specified for me is likely to be and, in practical terms, quantitatively how much that there is in the way of reliability issues (do these systems fail every year? Two years? Ten years? Do they need maintenance more often than, for example, a gas boiler's annual inspection? How much does this vary between types?). Any insights into this would be appreciated.
Fourthly, in terms of the PV, it is difficult to know how best to size the system. The 6.32kW peak value for having panels on east, west and south facing roofs would generate plenty of electricity in the summer, but it is difficult to know in practical terms how much and how this would interact with the battery storage amount. A larger array would, of course, generate more usable amounts of electricity on less sunny days, but I do not know how much more in practical terms that this would be. Adding more panels seems less expensive than adding a further battery - but it is difficult to find good resources on ideal battery sizings, especially for a household whose heating is by way of a heat pump combined with solar thermal for hot tap hot water (DHW). This also makes it impossible for me to compute the ideal battery size based on my current usage.
Fifthly, cylinder size - it is very difficult to calculate what size that I will actually need in light of my usage, as described above. Any assistance would be appreciated.
Finally, I should be interested in anyone who has knowledge as to whether the equipment that has been specified is optimum.
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