(24th October 2014. Some of the comments submitted here in recent days have been abusive and off-topic. I will remove all comments placed on this post until November 3rd 2014 in order to let things calm down. I know that many people find the expertise available from some of the regular correspondents here extremely useful so I will open things up again on November 4th 2014. Please completely avoid personal remarks, unpleasant accusations and off-topic comments on the quality of climate science).

(24th July 2013. Several commenters have kindly provided detailed analysis of some of the reasons why air-to-water heat pumps may be costly to operate. Others state that the technology is not at fault and blame the poor quality of the installation. Thank you very much to all those who have given time and thought to this issue. May I strongly recommend reading the full range of comments below the text? Chris)

When temperatures in the British Isles drop to unexpectedly low levels, the pattern of traffic on this web site changes. One set of search terms dominates the inquiries. Readers are looking for information on why their air source heat pump is costing so much money to run. Sold to them as a way of saving cash, readers often seem to find that the price of heating their home has suddenly increased, sometimes quite dramatically. And, moreover, the pumps don’t heat the house properly.

Today (March 25th 2013) is unusually cold across Britain and the search term ‘problems with air source heat pump’ is the single most common inquiry. Colder countries that have been using heat pumps for decades seem to be able to install them in ways that mean that homes have inexpensive and reliable heating. In the UK, with its badly insulated houses, air source heat pumps seem to be a complete disaster for many unlucky purchasers.

Below, I copy a letter I’ve just received from a lady living in the Orkneys off the northern tip of Scotland giving her experiences. Readers may also be interested in the comments added at the end of a previous post on heat pumps, including the most recent one from Jane Smith, submitted today. Despite the increasing evidence of systematic problems with air source heat pumps, government bodies such as the Energy Savings Trust continue to say that they will save money for householders living off the gas grid. Heat pumps are also part of DECC’s ‘Renewable Heat Incentive’, a scheme that is intended to subsidise the installation of suitable and effective technologies for householders. The continuing official support for heat pumps in the face of repeated failure needs to be challenged.

(Published with permission from Ms Switsur)

Hi Chris,

I don't need a reply to this, I am just having a grouch which might interest you.

AIR SOURCE HEAT PUMPS are USELESS for anyone on a low income. I am 72. I have £130 a week total income (Pension and Pension Credit). My house had no central heating. The Energy Savings Trust conned me into having the Government Grant of £6800 and paying £2000 extra myself to have air source central heating.

It took 11 months to install because the plumber obviously didn't know what he was about.

The first winter my leccy bill was nearly £400, and I thought it was my fault for not using the system properly, and it took me a very long time to realise that the installer had left the hot water boost permanently on.

This winter I really, really tried to economise, turning rads down and only having it on in the cheap periods. Result? a bill of £420. As I also had unexpected vets bills and an insurance excess of £250 to pay because my car slid in the snow and did some damage, I could not pay the bill - there is only £90 left to pay but (the suppliers) are saying they will cut the leccy off if I don't sign up to their payment scheme. I can't afford their payment scheme anyway because it is double my weekly payment.

My electricity costs are now more than 20% of my total income even thought I was promised I would save money. I HAVE SWITCHED THE SYSTEM OFF and gone back to coal. 11 months of torture while the thing was installed, £2000 of debt to pay my share, and I am back exactly where I started.

Please do advise people on low incomes not to bother with it. It didn't heat the house adequately in cold weather anyway.

Thank goodness I have an open fire!

Regards, Julie

Julie Switsur Ardage Burray Orkney KW17 2SS