We had a heat pump installed by Octopus last year at a cost of £11,500. 

Our experience with the heat pump has been a disaster, primarily as it only heats the home to a maximum of 18 degrees.  Some rooms struggle to go above 12 degrees. 

Our home is only 20 years old and well-insulated.

The bills are now higher than before we had the heat pump installed, and were up to £20 per day in the winter. 

Octopus says the system wasn't designed to heat our home above 18 degrees. 

This was never mentioned to us and we would never had agreed to such low temperatures. S.C., Gloucestershire

Helen Crane, This is Money's consumer champion, replies: You were trying to do the right thing for the planet and go green, but ended up with a heat pump headache that lasted for months. 

While 18 degrees isn't freezing, it certainly isn't ideal on a cold winter's morning - and the rooms that dropped below 12 would have felt very chilly indeed. 

You felt you'd traded in your old gas-guzzling boiler for an inferior model. 

You paid £11,500 for the pump and installation, of which £7,500 was covered by a grant from the government's Boiler Upgrade Scheme meaning you put in £4,000. 

On top of that, you were losing more cash because your bills had increased since the heat pump was fitted, despite it generating energy from heat in the air rather than gas like your previous boiler. You were now paying between £200 and £300 per month. 

The house is only 20 years old, so should be cheaper to heat than older properties.  

But in deepest winter, you were paying £20 per day in some cases despite not being able to properly warm your house. 

What's more, the heat pump had been installed on the wall outside your lounge and below your bedroom, and the device was noisy.   

You worried that you'd been rushed through the sales process and sold a heat pump which wasn't right for your home.

You first contacted Octopus to tell them about the not-so-hot heating device in November. 

An engineer visited and told you the system was working properly, but helped you schedule it so the heating came on at the right times. 

But the temperatures reaches stayed the same, so you contacted Octopus again in December. 

Between then and March you were repeatedly fobbed off with empty corporate platitudes, being told your problems were being 'actively reviewed' and a solution was being 'discussed internally'.

At one point, the manager assigned to your complaint ignored eight emails from you in row, all of which were polite requests for an update. 

You also escalated it to Octopus boss Greg Jackson, who makes his email address public, twice as well as referring the case to Napit, the certification body with which Octopus heat pump installers are registered. 

Still no one came out to fix the system, and you were left sitting in a house that was lukewarm at best throughout the coldest months of the year.

At the beginning of April, you contacted me. You said you were happy to keep the heat pump, but only if Octopus can find a way to make it work properly. 

If not, you wanted the firm to put a boiler equivalent to your old one back in and refund your £4,000.

The firm investigated your case. 

It said that according to industry standards, heat pumps were designed to heat bedrooms to 18 degrees and living spaces to 21 degrees, adding: 'For the vast majority of our customers, they keep homes comfortably warm while reducing bills compared with a traditional gas or oil boiler.'

Octopus said these temperatures were included in your final contract but recognised it 'should have explained this more clearly during the initial sales conversation.'

When you continued to raise concerns about low temperatures and higher bills after the November visit, it said it 'should have escalated the issue much sooner.' 

After I got in touch, your case was reviewed by Octopus' technical director. 

They found that, while the heat pump itself wasn’t faulty, the home was losing slightly more heat than its original calculations predicted due to 'variations in the home's fabric, including areas of uneven loft insulation.'

To put things right, the firm said it will carry out all the necessary work to improve the home’s heat retention and make sure it reaches the temperatures you expect. It will also refund the £4,000 you paid.  

It also said it had used your case to review and improve its after-care service for heat pump customers.

You said: 'Thank you again for your involvement which I am certain helped move things along, and for the work you do on behalf of members of the public.'

Work is now under way at your home. 

While it might seem a long way away during this week's heatwave, I hope you can look forward to a warm and cosy winter ahead.