Renovating and extending, A2W heating system

2020herewego

Hello,
We viewed a house today with engineer, it's an old house built 50 years ago, 65 square meters. We are hoping to build an extension to the back of the house of 40 square meters.
The engineer has recommended putting in an air to water heating system. He also said we could opt for oil heating system.
Is there much of a difference price wise to installation and running cost?

Calahonda52

For any heating system but especially a HP, you do need an airtight house so you need to get the controlled ventilation strategy designed and implemented first, you then need a decent level of insulation.
Assuming you have both of these
Optimal running costs for a HP come from using a night rate meter with a buffer tank and UFH
less Optimal running costs for a HP come from using a night rate meter and UFH
Even less Optimal running costs for a HP come from using a day rate meter and radiators.

Oil is currently about 5 cents a kWh this artificially low as its summer time and covid [ 50 cents a litre= 10 kWh)
NR elec might be 10, at a COP of 3 makes it 3.3

HP will be dearer to install but the LCCA will show it cheaper, once oil prices go up and carbon tax hits 80/100 a tonne