I'm getting a heat pump - how beneficial would going to double glazing be?

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mmd

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#268448 20-Mar-2020 11:42

I live in a 2 storey apartment in Auckland CBD. I'm on the top floor of the building. I have insulation in the ceiling above me, insulation below, none in the walls. I only have 1 wall that faces the outside - this has some large windows / slider door for balcony in it as the room that faces the outside is 5.8m high.

I've been stalling on getting a heat pump installed because I figured it would be a good time to get the windows replaced with double glazing at the same time. However, my neighbour who has done this tells me that I can only replace the glass and will not be allowed by the body corp to replace the frames as well.

Am I going to benefit from switching to double glazing at all? Should I just get the heat pump install done because the benefit (or even payback for that matter) from double glazing will be that low? Maybe I just get some of those 3M "double glazing" stick-on sheets on the windows instead? Part of the reason I wanted the double glazing too was to help with noise levels from the outside.

What's everyone's thoughts? :)

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#2442044 20-Mar-2020 11:50

Theres a few retrofit double glazing outfits. Have a google but I cant tell you if retrofit is any good or not.

How thick are these frames? Pictures?

kobiak

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#2442046 20-Mar-2020 11:53

yes it will be beneficial especially for the larger windows as heat loss would be higher. Double glazing will reduce heat loss, but you still need the heat source if you don't use anything at the moment - you will be warmer with double glazing. or if you still use some heating - you'll use less on heating. heat pump would be more economical to run vs other heat resources.

I'm in townhouse with insulation all over the place, but not the 1st level floors and single glazing for all the windows. and 1 heat pump is enough to heat large lounge and 2 bedrooms above the lounge. Double glazing would be amazing I guess in my place.

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mmd

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#2442050 20-Mar-2020 12:02

Standard aluminium frames like you'd find in any 2000s house.

Didn't want to oversell the size of the windows, so here's a photo of them. The intended location of the heat pump would be as hard up against the ceiling as possible, in between the 2 windows in the middle. The master bedroom is upstairs so the heat pump could heat or cool upstairs and downstairs, wherever I wanted to be in the apartment at the time.

timmmay

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#2442051 20-Mar-2020 12:03

A heat pump will still lower your heating costs regardless of the windows. If you can't change the frames then let us know what you have already.

Don't do the cheap plastic film, it won't help with sound and it's a nightmare to get off. I had them on for one winter, when it came off I had to repaint all my window frames, was really annoying and time consuming. Plus all through winter you have to use a hair drier regularly to make sure they're on tight. Don't do it.

mmd

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#2442053 20-Mar-2020 12:08

timmmay:

A heat pump will still lower your heating costs regardless of the windows. If you can't change the frames then let us know what you have already.

Don't do the cheap plastic film, it won't help with sound and it's a nightmare to get off. I had them on for one winter, when it came off I had to repaint all my window frames, was really annoying and time consuming. Plus all through winter you have to use a hair drier regularly to make sure they're on tight. Don't do it.

Thanks for the advice against the film - will not proceed with it.

Standard single glazing, windows posted above. The only other openings in the apartment are the front door to the apartment itself, as well as a skylight in the ceiling that can be opened. The skylight has a wooden frame (go figure). And for unrelated reasons I'm replacing this skylight with a rain-sensing aluminium frame double glazed skylight soon anyway, so it should be a non-issue soon, hopefully.

NOTE: I have NO heating source at the moment whatsoever. I've only purchased this place and moved in 6 weeks ago.

ben28

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#2442069 20-Mar-2020 12:25

I’d get the heat pump and see how it goes this winter If you have curtains across the windows they’ll do a better job than double glazing
Obviously only relevant at night.

ben28

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Technofreak

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#2442123 20-Mar-2020 12:52

mmd:

Standard aluminium frames like you'd find in any 2000s house.

Didn't want to oversell the size of the windows, so here's a photo of them. The intended location of the heat pump would be as hard up against the ceiling as possible, in between the 2 windows in the middle. The master bedroom is upstairs so the heat pump could heat or cool upstairs and downstairs, wherever I wanted to be in the apartment at the time.

Before you decide on the location of the heat pump you need to think about what you want from it.

If it's heat you want then it will work better located lower rather than higher. Heat rises.

We have a 6 kw floor mounted heat pump and it does an excellent job of heating downstairs and a pretty reasonable job of heating up stairs. Downstairs is open plan so no control of where the the air flow goes. While the upstairs area has doors on the all of the rooms there is no barrier to the air flowing upstairs. So it's heating a reasonable size area.

When it comes to cooling, the downstairs area gets cooled nicely but there is almost no impact on the temperature of the upstairs area. Cold sir sinks. A high mounted heat pump would do a better job for cooling.

Mounting the heat pump as high as possible may not be your best option. Since heat rises it will be hard to heat areas below the heat pump. In other words the reverse of the problem we have with cooling the upstairs area with a low mounted heat pump.

For heating I would highly recommend a floor mount model, for cooling I think a high wall mouted model may be the better option.

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kotuku4

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#2442156 20-Mar-2020 13:26

A standard aluminium window and frame has a R value (insulation, thermal resistance) of 0.15 and typical double glazed 0.25 -0.3

An insulated wall R2.6

So double glazed windows can be twice and good as single, a noticeable difference. But still a fraction of an insulated wall.

Also consider good blinds with honeycomb/ air cell.

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scuwp

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#2442201 20-Mar-2020 14:08

Heat pump and some decent thermal curtains...and see how you go this winter. My 2 cents.

Lazy is such an ugly word, I prefer to call it selective participation

NightStalker

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#2442231 20-Mar-2020 14:47

have a look at Energywise - Retrofit alternatives to double glazing

They have some options that may be doable for your situation and they may be able to put you in contract with someone to do it.

eg - "installing separate aluminium framed secondary glazing on the inside of the existing glazing - typically installed as sliding panes in frames fixed to the internal window sill, jamb and head reveals"

Scott3

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#2442237 20-Mar-2020 14:56

For acoustics you are better off with "secondary glazing" than double glazing. - I.e. another window 100mm inside the existing one.

Not as good thermally as the gap is large enough for thermo-currents to start in the trapped air.

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Dugimodo

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#2442239 20-Mar-2020 15:05

I had my windows done by metrofit and there's a very noticeable difference in noise and condensation and a lesser difference in temperature. But I also got rid of my net curtains which have a surprising amount of effect on insulation because they trap some air between the net and the glass so that countered some of the gain.

A decent set of curtains would really help as others have said, and wherever possible take them all the way to the floor. Not possible for your high windows but for the other window you can. If you want to leave the top windows permanently exposed then double glazing them is all you can do.

Metrofit replace the glass and beading in your existing frames and I've been very happy with the results personally.

mmd

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#2442299 20-Mar-2020 16:36

Technofreak:

mmd:

Standard aluminium frames like you'd find in any 2000s house.

Didn't want to oversell the size of the windows, so here's a photo of them. The intended location of the heat pump would be as hard up against the ceiling as possible, in between the 2 windows in the middle. The master bedroom is upstairs so the heat pump could heat or cool upstairs and downstairs, wherever I wanted to be in the apartment at the time.

Before you decide on the location of the heat pump you need to think about what you want from it.

If it's heat you want then it will work better located lower rather than higher. Heat rises.

We have a 6 kw floor mounted heat pump and it does an excellent job of heating downstairs and a pretty reasonable job of heating up stairs. Downstairs is open plan so no control of where the the air flow goes. While the upstairs area has doors on the all of the rooms there is no barrier to the air flowing upstairs. So it's heating a reasonable size area.

When it comes to cooling, the downstairs area gets cooled nicely but there is almost no impact on the temperature of the upstairs area. Cold sir sinks. A high mounted heat pump would do a better job for cooling.

Mounting the heat pump as high as possible may not be your best option. Since heat rises it will be hard to heat areas below the heat pump. In other words the reverse of the problem we have with cooling the upstairs area with a low mounted heat pump.

For heating I would highly recommend a floor mount model, for cooling I think a high wall mouted model may be the better option.

Some excellent informative responses, everyone, thanks a lot! Sounds like I am going to go ahead with the heat pump regardless and let the double glaze vs single glaze decision be one I do in the future. Also sounds like maybe the roller blinds need to be replaced with something else. I need to confer with the Body Corp here.. I think they have some rules around the color of blinds I can choose, lets see!

In response to your point here, Technofreak, I do want the heat pump for both heating and cooling purposes and understand the concept of heat rising. My aim to put the heat pump at the top there is this - it can blow air horizontally (my bedroom upstairs has a half height wall, i.e. is open horizontally with line of sight to where the heat pump would go), and it can also blow downwards. So pending where I am in the apartment, I can get the heat pump delivering cold or hot air to me.

While I have walls and doors downstairs, its all pretty much "open" as I could just leave doors open and the whole apartment would get heating or cooling. While its a 2 bedroom apartment, I'm using the bedroom downstairs as a study, and I live alone, so not concerned about closing doors etc.

Here's a floor plan that gives a better view of the place!

Technofreak

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#2442329 20-Mar-2020 17:27

I fear you will be really disappointed with the heating results if you install the pump as you indicate.

I think you are expecting too much from that pump to adequately heat the downstairs area. Base on our experience with the cooling ability of our pump, if we were intending to stay in our current house long term we would be installing a second pump upstairs.

Another factor to consider is even though you can blow the heated air downwards the heated air will still rise. Also the air being drawn into the heat pump will be warm air rather than cold or colder air if it were mounted lower. Having a heat pump mounted lower rather than higher for heating is a very effective way of mixing all the air in the room and warming the colder air. The converse applies for when the cooling mode is used.

I think you may need to consider two pumps or a ducted system to gain the desired results.

One other thing to consider is the draught created by the airflow from the heat pump. This can be quite annoying for many people, careful location of the pump can minimise the effects of this.

I am not a heat pump expert, my comments are purely based on personal experience. I would urge you to get some good advice on the best location prior to hitting the Go button.

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Jase2985

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#2442378 20-Mar-2020 17:51

i would be installing a fan in the void space which will help circulate the air then a heatpump just above the windows down stairs

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