Alastair & Helen’s Energy Efficient Home

Draughtproofing Heating and hot water Renewables and storage Technology & Renewables

After previously retrofitting their previous home, Alastair and Helen were driven to have their new home running as cleanly as possible. They installed solar panels, a battery, heat pump, new radiators, a smart hot water cylinder, and an EV charger.

Summary

Export maximum 5kw of energy to the grid

The heat pump has an efficiency of 325%

Daily energy costs averaging <50p a day

The Home

House Type: Detached, early-2000s
No. Bedrooms 4
Wall Type: Cavity
Area: North Somerset

Overview

Alastair and Helen moved into their North Somerset property in 2021. After retrofitting their previous home, Alastair and Helen were driven to have their new home running as energy efficient as possible without compromising the functionality. They installed solar panels, a battery, heat pump, new radiators, a smart hot water cylinder, and an EV charger.

Background

After living in their new property for six months, the couple realised how inefficient their new home was compared to their old one. When they moved in, they had a D-rated Energy Performance Certificate (EPC) compared to the A-rating they had reached previously. Their roof faces all four main compass directions, no trees are blocking the roof, though in mid-December, an adjacent property casts some shadow on the east-facing roof at the end of the day. They have a suspended floor on the ground level, and a decommissioned gas fire chimney.

Their goal was to run the house as cleanly as possible while generating enough energy to meet their needs and contribute to a greener grid. They opted to install solar panels with a battery to store the solar power as well as a heat-pump with new radiators and a hot water cylinder, totalling around £24,000 total. They also brought an EV charger from their previous house (as the new owners didn’t need it), which was worth £600.

The Renewable Heat Incentive (RHI) payments offset a considerable amount of the heating system installation costs, and their operational electricity costs are lower despite the increase in consumer electricity rates.

Assessment

Alastair and Helen examined a variety of options, from thermal infra-red panels and electric boilers to heat stones and phase change systems, as well as various types of batteries. However, they decided it was vital to consider the operational aspects of heat pumps and batteries. While there’s plenty of information available on how they work, there’s less information on what it’s like to use them regularly.

They were eager to see a domestic heat pump up close, so reached out to their community on the community platform Nextdoor to find someone who could demonstrate a heat pump. They had some fantastic conversations with individuals who had years of experience living with air-source heat pumps in Scandinavia and working as heating engineers in the UK.

After installing the heat pump, they conducted a CHEESE thermal imaging survey. Ideally, this survey would have been conducted prior to installing measures but, Alastair and Helen had already had their gas disconnected, so they needed to go ahead with the heat pump installation immediately to heat their home.

The thermal imaging survey allowed them to locate where heat was escaping, or in this case, where cold air was leaking into the house. They discovered a gaping hole in the plasterwork behind the bath, which led them to an uncapped gap in the attic next to an outside vent. This created an unblocked chimney effect, drawing cold air into the house. They now understood why the bathroom always felt chilly.

The Challenge

During the installation of the hot water cylinder and heat pump buffer tank they faced a few challenges. First, they had to find a spot for everything in the airing cupboard, but quickly ran out of cupboard wall space, so the Daikin heat pump controller had to be installed just outside, on the landing wall.

To ensure efficient heating, they agreed that most of their radiators would be up sized. They decided to keep the kitchen, hall, and bathroom radiators, but the bathroom radiators will be replaced when they update the bathrooms in the future.

The pandemic forced some key people to isolate throughout the main installation period. The project was also hampered by the cold and wet weather as the installation took place in early January.

Results

Their energy bills have been significantly reduced, with most days costing less than £1 on imported electricity. The heat pump has been highly efficient since its installation, running for 454 hours in the first year and supplying 2716 kWh of heat while consuming 836 kWh of electricity. In fact, it has an efficiency rate of 325%!

Energy usage details:

Total usage: 2353 kWh
Solar production: 5303 kWh
Grid usage: 216 kWh
Solar generation sent to the grid: 3059 kWh

Alastair and Helen can export up to 5kW, meaning their neighbours can make use of the clean electricity generated by their system. The couple’s daily costs have remained low, averaging 33p per day, and they have also arranged for a smart export guarantee payment which generates income from the exports. Although still low compared to import costs, the export payment rate doubled in 2023 to 8p per unit.

The solar panels, battery, car charger, and hot water cylinder have all been excellent investments and the couple are considering a second battery and new windows in the future.