Conversation

George Brown: Hello Tim.

Tim Smith: Hello George. It’s great that you could find the time to come so quickly. We’ve got quite a few things that need discussing.

George Brown: The technical matters, I assume.

Tim Smith: Yes, that’s right. I don’t know if you’re aware, but all buildings nowadays have to be built according to the new building regulations, which have been adapted to incorporate some of the clauses from the European Directive. This generally means lots of insulation and a low energy demand.

George Brown: Right. Does that mean a passive house or something like that, then?

Tim Smith: Well, a passive house is a standard which can be achieved by fulfilling certain requirements. It’s a design philosophy, but you can also have it certified.

George Brown: What might I need a certificate for?

Tim Smith: Well, more than anything it might make you feel good and might encourage others to do the same. There are, however, government schemes that subsidise green building. I’d have to find out exactly which ones might be appropriate. I know though that the government is subsidising heat pumps and off-grid power.

George Brown: Oh, do you mean we could generate electricity with those solar panel things?

Tim Smith: Well, that’s one possibility. There’s also the possibility to generate electricity with a micro generator. A micro generator would produce heat and power and, if you use a renewable energy source like wood pellets or chips, it could even be carbon-neutral.

George Brown: Mm, interesting. So what are the requirements for a passive house?

Tim Smith: (takes a look at his notes) The annual heating demand must be no more than 15kWh/m², which can be achieved with approximately 15 cm of insulation and triple glazing. The total primary energy demand must be no more than 120kWh/m² per year, so this also means lots of daylight, energy-saving appliances, like the washing machine and so on, and the building must be airtight, to be precise it may not leak more than 0.6 times the house volume per hour.

George Brown: My goodness all that insulation and triple glazing. Will we be able to breathe?

Tim Smith: Actually, that is a problem in these new very airtight buildings. And if we do go down this route, we’ll have to make sure the ventilation is sorted.

George Brown: Do you mean, we’ll be needing an air-conditioning unit?

Tim Smith: No, we’d use a fairly simple heat recovery ventilation system. Basically this provides a regular exchange of air without loss of heat in winter or cool air in summer.

George Brown: What about solar panels though? It is the trend, isn’t it? Couldn’t we generate hot water in the summer and also electricity?

Tim Smith: The roof that we’ve planned is actually perfectly inclined and oriented for the use of solar panels. If we do fit them, there will be a cost saving on roof tiles.

George Brown: This is all quite complex and there are a lot of numbers involved. I presume the costs are also quite considerable, too. We’d like to go green, that’s one of the reasons why we’ve commissioned you. On the other hand, our budget is limited and I’m no expert when it comes to these technical matters. Could you draw up a realistic scheme that will meet passive house or low-energy house standards for us to discuss at our next meeting?

Tim Smith: That sounds good. I’ll set up a meeting with our building services engineer and together we’ll draw up a plan including the necessary building services and update the cost estimate for your new home.

George Brown: Great. Thanks. Let’s fix a meeting for next week then.