A new self-build home finished spring 2024 using a Potton timber frame system with outer walls finished with concrete block and K Render.
The house design is contemporary, with colours to match the seas and cliffs of Charmouth.
Energy Performance (EPC)
The house is rated as “A” scoring 105% under the current assessment scheme. The house is one of only a few properties in Dorset which score over 100% EPC. An average house produces approximately 6 tonnes of CO2 per year, but Lower Reaches annual CO2 is approximately minus 2 tonnes per year. The house achieves close to Passivhaus standards, but it is not on their register as we wanted lots of windows to take advantage of its coast and beach location.
Energy Production
28 PV panels on roof, with 14 south facing and 14 north facing on each side of the house generating approx. 7 KW/hr during daylight for about 7 months in the year. The site however has 14 trees which shade the house for approx. 2 hours a day. Also installed are 3 Libbi batteries which store about 15KW with the surplus exported.
Heating & heat recovery and ventilation
A Mitsubishi Coastal Air Source heat pump rated at 11KW running through under- floor heating pipes and heating hot water.
A Contura wood burner is fitted and rated at 5 KW which can heat the whole house.
A Rega Mechanical Ventilation and Heat Recovery system is fitted to move and recover internal heat and redistributes the heat around the house. The system also takes in outside fresh air and filters it and circulates it around the house.
Exhaust air from bathrooms and toilets is removed and vented to outside removing any heat before hand..
Energy consumption
There is no gas in the property. All lighting is low energy bulbs and overnight the house consumes around 600W/Hr.
The Libbi storage batteries supply up to 15KW until exhausted, and then take up to 4 hours to recharge.
2 Zappi car chargers are fitted on the house, and we use the Octopus Energy tariffs to manage electric inputs and exports. The main car is a plug-in Toyota RAV with a 50 mile range battery. This is charged overnight at 7p/KW. As we are paid 15p/KW for our export then it makes sense to use grid overnight electricity to charge the car. This however makes the import electricity value higher and appears to be less efficient!
Water and Rain management
The property has a Sustainable Urban Drainage scheme “SUDS” which simply means that all roof and surface rain- water drains into underground rain cages and does not enter the public sewer system. The roof rainwater can be used to irrigate the garden. A new well has also been dug further down the garden.
The house has now is placed in a “Management Realignment Zone” which means no further coastal defences will happen at Charmouth and the sea will be allowed to flood the river valley. We are actually a potential climate change victim, as they have said that the houses will no longer benefit from any protection.
CO2 + Nox Capture
The lawns are sprayed monthly with a Nitrous oxide capture product called R-Leaf, which converts poisonous Nox into plant food to feed the lawns. The effect of this is that about 500kg of CO2 equivalents is converted into free lawn fertiliser each month. This could be added to the minus 2 tonne CO2 value shown in the energy certificate, but this is a future discussion.
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The house can be found on this google map link