Heating v Insulating v Ventilation, which first?
We have some double glazed windows in our home, some not. All are aluminium. Windows approx 20 years old. We are considering double glazing the bedroom windows. Do you do this or use the money required for this to install a HRV or similar… or heatpump even? We are on a single wage and want to make the best most efficient cost effective use of our money.
January 19th, 2010 at 9:18 pm
Hi there,
Thanks for your post. You dont say whether you have already put in ceiling and underfloor insulation (to current building code standards wherever it is possible).
We would recommend doing these two measures before considering further double glazing or a heat pump.
Aluminium windows do not offer much thermal resistance, particularly if they are “thermally unbroken” ( that means the aluminium frames connect right through from the inside to the outside, allowing heat to flow out through the frame). A single glazed aluminium window has an R value of 0.15. However double glazing a thermally unbroken older style aluminium window will only improve this to R 0.26.
Compare this with putting in wall batts into your walls and taking the R value from around R 1.0 to around R 2.0 for the whole wall (which is usually a bigger area than the window)
For this reason, in my opinion, in most homes the best value for money is to provide well fitted thermal backed and lined curtains for existing windows, especially in the living areas (good curtaining or quality fabric blinds can add an R value of 0.5-0.8) but otherwise to concentrate on insulating ceilings and underfloor, eliminating draughts and removing gib and putting in wall batts before double glazing existing windows.
Energy efficient heating is also important as even a well insulated house will not be warm in winter without some additional heat. So if you are using ordinary electric heaters, an open fire, or a portable gas heater, I would suggest more energy efficient heating should be installed once ceiling and underfloor insulation, curtaining and draughts have been addressed.
We do not usually recommend putting in a DVS system unless you have made all the other energy efficiency improvements including addressing issues of ventilation and excessively damp ground under your house and there are still persistant issues with condensation.
I have covered a lot of topics here, so I hope you have found this helpful and not too confusing. If you would like to speak further to one of our advisors, feel free to ring on 0800 388 588. If you are out of our tioll free area, you can still call on a landline or email us by using the webform.
Best wishes,
Sarah Free (energy advisor, Wellington region)
March 1st, 2010 at 11:09 pm
Hello I live in Dunedin and I am thinking of changing a night store heater in a hallway to a heat pump. The night store is not getting warmth into our main bedroom nearby.
What is your view regarding runnings cost ( power usage) and heating efficiency. I do have Moisture Master which had reduced condensation in the bedroom windows by about 60-70% but not entirely. The bedroom is located on the cold side of the house as far as sun goes. It would be nice to have the back half of the house kept up to about 18 degrees as economically as possible.
April 5th, 2010 at 5:41 am
Howdy, always Insulation first in my opinion otherwise your leaking heat out of your house at a torrid rate of knots.
As far as the HRV goes remeber its a ventilation system not a heater however in saying that alongside Insulation and Heating I believe the 3 mke a perfectly balanced house.
being in the hvac industry for a while now id reccomend Mitsubishi Electric heatpumps (definitly the hypercore models if possible) and HRV for your Ventillation,cant say im fond of DVS at all.