Green heating systems can be a nightmare
This article was sent by a correspondent who wishes to remain anonymous.
We built a new house seven years ago, after spending two years researching the best, most modern way to construct it, with a view to managing the increase in energy prices. After consulting several architects and heating consultants, we decided on a thermal mass house construction, I won’t go into too much detail, but essentially it means building a house using a solid interior structure and then heavily insulating the exterior walls floor, roof and using thermal-insulated aluminium window frames and triple glazing.
However, the main concern
was the type of heating system. We consulted four heating consultants to try
and establish the best system to install and this is when the fun started. Again,
I will not go into too much detail of the options, but we were astonished at
what we were told.
Installation would be quite
expensive and the system would not be particularly efficient. Although we had a
south-facing house, the roof area facing south was not large due to an earlier planning
restriction on the roof height. The consultants explained that solar would not
give adequate heat anyway, and we would need to supplement it with either gas,
oil or a heatpump.
When pressed, two of the
consultants admitted that air-source heat pumps had issues: the cost of supply
and installation, the space requirement, and there can also be noise issues. But
the bombshell came when they stated that air-source heat pumps lose efficiency
at around 2–3°C. Below freezing, the air-intake vanes need heating with an electric
element; otherwise they seize up and can’t be used. We were shown a graph, demonstrating
that the drop off in heat recoverable at low temperatures was dramatic, and we pointed
out the obvious concern that cold weather was when we need the heat. It was
explained that we would then require a supplementary heating source, such as electricity,
gas or oil.
A ground-source heat pump
and the associated equipment carries a capital cost of tens of thousands of
pounds. It also requires a large area of garden, to be excavated to around 2
meters depth, for the underground pipes. Alternatively, it is possible to bore
a hole deep into the ground instead, but precisely what depth is unknown and depends
on the strata below the house. There would be no guarantee of the energy output
gained by this method, so we would have no idea if the spending would deliver
adequate heat and hot water.
The costs varied depending
on the supplier, but as a ballpark figure the solar came in at around £9,000,
the air source pump/exchanger around £8–10,000, the ground source heating in
its flatbed variant at around £16,000, rising to £23–30,000 for a borehole
variant, depending on the depth and the size of heat exchanger required. It
should also be noted, that the heat pumps would require a high input of
electricity to work the pumps and heat exchangers.
In the end, the two candid
energy consultants admitted that the mains gas that was already available in the
village would be the most cost-efficient approach, even with our
high-efficiency thermal-mass house construction. In their opinion, the other
forms of heating were more suitable for areas off the gas grid. Unsurprisingly
then, we opted for gas.
We are glad we researched
these questions so carefully. I have recently read several articles about newly
constructed houses whose owners have installed green energy systems and have
then had to cope with energy bills running to thousands of pounds per annum,
even for modest dwellings. Even Kevin McCloud of Grand Designs fame was
involved in one of these projects.[i]
To end, even with our
expensive build we have seen our energy bills increase by almost 55% in the seven
years since we moved in. This is despite us never having used the upstairs
heating and the underfloor heating of the ground floor operating only as and
when required to maintain the ambient temperature in the living areas. The
electricity element has been the main driver.
Who do they think is going
to buy the new green ecohouses? Are developers going to be honest with
prospective owners about the energy costs they are going to be taking on? Electrical
heating on cold days in winter will not come cheap. It won’t take long for the
true cost or heating these properties to become public knowledge. The building
industry should simply refuse to go along with this madness.
via The Global Warming Policy Forum (GWPF)
March 12, 2020 at 04:18AM