Heat Loss Calcs - Air Changes

[machineage]

Hi again everyone

Just about finished all my heat loss calcs with Stelrad Stars.

I just wondered about the ventilation / air changes. These significantly affect the heat requirements.

Currently they are set as the following changes per hour :

• Living Room - 3
• Drawing Room - 3
• Dining Room - 2
• Hall - 2
• Kitchen - 3
• Utility Room - 2
• Landing - 2
• Bathroom - 3
• Bedrooms - 1.5

All the upper floor rooms have double glazed windows. The ground floor rooms are mostly single - weatherstripped - soon to be double glazed. Ground floors are suspended timber. Living & Drawing rooms have open fires with requisite chimneys.

Are these air changes per hour about right?

[AWheating]

without checking my notes i think i normally allow 3 for rooms with extract fan and 1.5-2 for other rooms. Its been about 8 months since i have done long hand calculations tho.

[fuzzy]

Hi again everyone

Just about finished all my heat loss calcs with Stelrad Stars.

I just wondered about the ventilation / air changes. These significantly affect the heat requirements.

Currently they are set as the following changes per hour :

• Living Room - 3
• Drawing Room - 3
• Dining Room - 2
• Hall - 2
• Kitchen - 3
• Utility Room - 2
• Landing - 2
• Bathroom - 3
• Bedrooms - 1.5

All the upper floor rooms have double glazed windows. The ground floor rooms are mostly single - weatherstripped - soon to be double glazed. Ground floors are suspended timber. Living & Drawing rooms have open fires with requisite chimneys.

Are these air changes per hour about right?

i use 1.5 for every room

[dontknowitall]

Slight tongue in cheek remark but don't these figures get thrown out of the window when the windows are open? And if it's blowing a gale ...

[machineage]

Would two changes suffice for the rooms with open fires (chinmeys) and suspended timber floors with plenty of underfloor ventilation?

The house by the way is a victorian semi with 10ft ceilings - and a bit draughty here & there - though I'm attending to that as best I can with weatherstripping etc.

[SimonJohns]

Lol. Just to add. New builds should have an air change of 0.5 per hour !!!!

[fuzzy]

1.5 should be fine, the size of the room is part of the calc in a different area so no need to compensate here as well