Ive been paying the landlord (office landlord) for electricity. But now I (and he) realise half of the roof has not been properly insulated. So Id like to know how much wasted electricity/money has gone through the roof.

If my office is 4400 sq feet, second floor, modern with double glazed windows on three sides. Is there an industry standard I can apply that will estimate my energy consumption to heat it ? Or what goes through the roof.

Just a rough estimate based on some science will do as a starter for negotiation processes.

Cheers.

Calculate the continuous los in Watts then multiply by 24 for the kWhs lost per day.

Assume U = .2 if there’s the usual 200mm of insulation and U = 5 if there’s no insulation at all.

Yes you can.

Calculate a loss through the current arrangement and the new arrangement and work out a wattage loss per m2 / per degree K.

So for example – old roof say 0.6 / new roof say 0.2 – difference over 4400sq ft (408m2) = 0.4 x 408 = 163 watts. However note that this is per degree K difference between inside and out.

So say 20 degrees inside / 5 degrees outside would equal 163watts x 15 = 2.4kwh per hour (call it 30p)

Cheers chaps – looks like I can get about 18k off my bill 🙂