Whole House cooling

[sargan]

I came across a neat solution in US

 

You have read that a neat way of cooling house in hot weather is to open the loft trapdoor and have a desk fan blow air into the loft ..... i.e. create a flow of air out of the house.

According to articles significantly cools a house down in the evening.

 

 

To reduce very high AC costs .... there is a neat system, where you have a grill on the upstairs ceiling.    In loft space, there is a 'chamber' with 2 exhaust fans.

When you press the remote 'on' button, pair of insulated doors open and fans such out the hot air ... (warmest is at ceiling level)

It does into loft space and exhausts through normal vents )ridge tile etc.

 

I did try Villavent and a few others but no luck, does anybody know if similar units are on sale in UK ?

 

https://www.tamtech.com/product/hv1600-2-speed-whole-house-fan/

[Roundtuit]

That would require a route for the air to get in to the house too; ie open your downstairs windows & doors.  Not much help over night, or with mvhr.

[SteamyTea]

It is also dependant latitude.

Most of the USA is on a latitude with Madrid or below, this means that the sides of the house has less time exposed to direct beam irradiation than in the UK, which is a minimum of 10° further north.

Most of the overheating in the UK is caused by a plume of hot air moving in from Europe and North Africa, venting a house does not help much then.

If solar is causing an overheating problem, better off putting a reflective film on the windows.

Edited October 26, 2022 by SteamyTea

[JohnMo]

Confused why modern heat pump derived aircon is expensive to run, with an equivalent of a CoP of around 6 to 10 depending on model and outside air temp.

[jonM]

I have a house facing east - west that was built to passivhaus standards with MVHR. PHPP modelled overheating (temp > 25oC) at 5% and in the first summer we did have a few problems with overheating but when we sorted the venting out it made a huge difference. Key points are:

 

1) If you can open all the windows you will gain the benefit of cross ventilation which makes a big difference. We tilt and lock the downstairs windows and tilt the upstairs windows.

 

2) Leave the internal doors open to allow the air to circulate around the house.

 

3) We have a small skylight in the roof which is left open and allows rising hot air to escape. 

 

4) Open the windows when the external temperature is less than the internal temperature and close the windows when external temperature approaching or higher than the internal temperature. 

 

Net result is that this summer the temperature downstairs has not exceeded 25oC and the temperature upstairs has only exceed 25oC on a couple of occasions in spite of the high temperatures we experienced. 

[SteamyTea]

12 hours ago, JohnMo said:

Confused why modern heat pump derived aircon is expensive to run, with an equivalent of a CoP of around 6 to 10 depending on model and outside air temp.

Is it really expensive to run, what is the kWh/K.m³ number?

Edited October 27, 2022 by SteamyTea

[JohnMo]

5 hours ago, SteamyTea said:

Is it really expensive to run, what is the kWh/K.m³ number?

 

Doesn't depend on a few different things, like solar gain through windows and fabric structure, the same or similar to heating

[joth]

Very popular in Denver, I think most family houses are built with them.

Being a mile high and very low humidity dessert conditions, the outdoor air temperature drops very low overnight even in the middle of summer, so extremely easy to cool a house by opening some windows and sucking the hot air out through the loft. 

https://www.coloradoenergygeeks.com/whole-house-fans

 

 

[SteamyTea]

4 minutes ago, joth said:

Denver

Good old Denver.

On a similar Latitude as Ankara, Turkey, though the temperatures are not so dissimilar to SE UK.