Heatpump replacement options for existing house

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tweake

2291 posts

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#2975813 1-Oct-2022 13:59

the outdoor units fins need cleaning every so often. with mine its usually spider webs. clean them off and give it a hose with detergent. biggest thing is regularly clearing any weeds/plants growing up around it.

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xlinknz

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#2975916 1-Oct-2022 14:46

tweake:

the outdoor units fins need cleaning every so often. with mine its usually spider webs. clean them off and give it a hose with detergent. biggest thing is regularly clearing any weeds/plants growing up around it.

Thank you for the reply

You can use a hose on the fan fans with no risk of water damage to any electrics?

I'll have a look and see how easy it is to remove the cover too, it is free of plants

tweake

2291 posts

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#2975922 1-Oct-2022 15:16

i usually pop the cover then hosing from inside out. but thats not for everyone. obviously power is off. also fan is on the other side of the unit but still don't go crazy and don't use high pressure.

what i would like to find is some foaming cleaner.

every location will be different, but i have cleaned inside heads 3-4x a year compared to cleaning the outside init once in several years. apart from cleaning spider webs off whenever i weed spray around the units.

timmmay

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#2975985 1-Oct-2022 16:11

I had my system serviced recently. The guy took off the cover over the fan and hosted a lot of dirt out from inside / around it, sprayed the coils, sprayed all around with bug repellent. It's weatherproof, you can hose it.

I only have the systems serviced every 2-3 years. In between those times I can do most of what they do myself fairly easily. Just watch what they do when you have them do it the first time.

KellyP

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#2976358 2-Oct-2022 15:29

Thanks for the replies and info team. Lots to consider.

stoffel

18 posts

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#2988251 26-Oct-2022 12:35

I'm after some advice on a ducted system.

We're in Auckland and live in a 230 square metre house that was built in the late nineties. The house has a positive pressure ventilation system (Moisture Master) which seems to do a pretty good job of keeping the house dry. There are three single split heat pumps in the house - one in our kitchen/living area, one in the lounge and one in the master bedroom.

The heat pump in the kitchen/living area (where we spend most of our time during the day) is at least ten years old and is starting to play up so I'm trying to decide whether to replace it with a new one or to bite the bullet and get a ducted system for the whole house.

I think a ducted system would work quite nicely in our place because in winter we spend most of our time in the kitchen/living area with the door shut and the heat pump on. We have young kids and it gets tiresome having to keep reminding them to close the door when they enter and leave the room. Also it would be nice to have a constant temperature throught the house which has obvious benefits with small kids.

Some questions:

1) If I get a ducted system installed is it worth getting rid of the the PPV system and using the existing diffusers on the ceilings or do I keep the PPV system and have additional diffusers in each room (might look a bit strange)? If I get rid of the PPV system am I likely to end up having condensation on the windows in the mornings? Ideally I'd like the house to be warm AND dry - with the current PPV I do have a dry house but it gets cold at night as the cold air from the roof cavity gets blown into the house.

2) One of the kids rooms faces west which means it gets very warm in there in the late afternoon/evening during summer and it is very difficult to get it down to a reasonable temperature by the time he goes to bed. I've read that ducted systems can struggle when one room gets significantly more sun than others. Would it be better to install a single split heat pump in this room instead?

3) Is it a waste having ducted air going into a room which already has a single split heat pump in it or can they complement each other? For example, we have existing single spilt heat pumps in our lounge and master bedroom. If we added a ducted system to the house we could set the whole house to a comfortable temperature (say 20 degrees) and then if we wanted the lounge or bedroom to be a bit warmer (say 23 degrees), we could just turn on the existing high wall units. Does this work?

mattenz

190 posts

Master Geek

#2988264 26-Oct-2022 13:11

Regarding PPV, you can get a 'fresh air intake' on most ducted heat pumps, which can come from the roofspace if you really want. Bringing in cold air and heating can be a good way to get dryer air. The drying mode on heat pumps always cools, as you may be aware.

You could use the existing ducts, but they might be underspecced on insulation and size, and current NZ standards suggest not having flexible runs of longer 6m (residential installers don't give two shits about that though). You'd almost certainly need more ducting to keep up with the ducted unit, they pump out something like 6-10 times the air of your typical PPV fan.

Sounds like you might need some zoning on the ducted unit. Combining with high wall units might not work as envisioned, probably depends on where your thermostat is for the ducted unit, and where the return/s are.

Part of the benefit of a ducted unit is not having high-wall eyesores, but probably difficult to justify uninstalling working ones.

timmmay

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#2988278 26-Oct-2022 13:55

stoffel:

I'm after some advice on a ducted system.

@stoffel Have you read the ducted heating guide I wrote? I have a Daikin ducted system, with an Airtouch controller, going into my lounge and bedrooms, but not into the kitchen / dining area. We did it because the kitchen gets a LOT warmer than the rest of the house, it's common to be cooling that room but heating the rest of the house.

I would be a little careful ducting a whole house including kitchen. Any cooking smells (fish, curry, etc) will get pushed into every room of the house.

Can one heat pump heat the kitchen / living area? If if could I would probably lean towards that. You could also do multi-split, one outdoor unit, two or three indoor units. They can be high wall or floor models. Then you could have a ducted system for the bedrooms, it would be a smaller one, probably the smallest available would do if the house has decent insulation. Minimum output is almost as important as maximum output.

I wouldn't have a ducted system without per-room temperature control /sensors. My sons bedroom faces north, I have Home Assistant set up to cool that room in the afternoon if it's too warm, then that turns off, a bit later the heating turns on if required. It's common for that room to be 25+ and the other rooms to still need heating some parts of the year.

To answer your questions.

1) It depends where the PPV vents are. You would want ducted heating vents opposite the exit from the room, which may be undercut doors or dedicated vents. The type of vents to use is also different. What we did is put the PPV diffuser beside the intake to the ducted system, which then blows fresh air around the house. The PPV system is on a timer so it only runs when we want it to run.

2) Make sure you get an Airtouch5 or similar. I wouldn't touch a ducted system without per-room temperature control.

3) This would work if you had an Airtouch or similar. Without an Airtouch, maybe.

angski

59 posts

Master Geek

#2988316 26-Oct-2022 14:47

empacher48:
tweake:

try to avoid multi-splits setups if possible. they are fine for doing multi heads in one big room but run worse when the heads are in separate rooms. even worse when there is a big difference in size. also the more heads the worse it gets. you get a situation where its a small head being run by a big compressor and it will short cycle badly. tho just two heads is not to bad, especially with variable compressors, even better if you can keep both heads similar sized.

Having installed Mitsubishi Electric heat pumps into 5 rooms (4 bedrooms @ 2.5kw and lounge @ 7kw) our installer told us to avoid a multi split system for the reasons you explained. Plus he also said the larger outdoor units used are made only in the Japanese factories to keep their technology in house and only produce smaller numbers per year. Where as the AP plus single splits we used are manufactured in other locations as they aren’t so concerned with their tech secrets for single splits to be leaked and can be mass produced in multiple locations. It also makes them cheaper to buy and maintain than waiting for exclusive parts from Japan.

Our installer only deals with Mitsubishi Electric heat pumps as he said in his 20 years running his business the rate of warranty work on them is a lot less than other brands.

I like the comment you have made.
Can I ask, given you have each heat pump per room rather than the multi split option, is the 7kW at the lounge enough to warm up the common area?
Did you ask for a comparison between a multi and individual heat pump?

thanks

tweake

2291 posts

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#2988352 26-Oct-2022 17:39

stoffel:

1) If I get a ducted system installed is it worth getting rid of the the PPV system and using the existing diffusers on the ceilings or do I keep the PPV system and have additional diffusers in each room (might look a bit strange)? If I get rid of the PPV system am I likely to end up having condensation on the windows in the mornings? Ideally I'd like the house to be warm AND dry - with the current PPV I do have a dry house but it gets cold at night as the cold air from the roof cavity gets blown into the house.

2) One of the kids rooms faces west which means it gets very warm in there in the late afternoon/evening during summer and it is very difficult to get it down to a reasonable temperature by the time he goes to bed. I've read that ducted systems can struggle when one room gets significantly more sun than others. Would it be better to install a single split heat pump in this room instead?

3) Is it a waste having ducted air going into a room which already has a single split heat pump in it or can they complement each other? For example, we have existing single spilt heat pumps in our lounge and master bedroom. If we added a ducted system to the house we could set the whole house to a comfortable temperature (say 20 degrees) and then if we wanted the lounge or bedroom to be a bit warmer (say 23 degrees), we could just turn on the existing high wall units. Does this work?

keep the PPV as is. odds are the outlets are in the wrong place for the heating system and ducts will need to be changed etc anyway. much easier to leave it as is.

let the heating do the heating and the ventilation do the ventilation.

the first thing really is if you want whole home heating or just room by room heating. heating the whole house will cost more but its actually far better. you really want to be running it constantly.

you can do a mixed system like ducted for the bedrooms and heat pumps for the lounge. thats because many people like bedrooms cooler.

itxtme

2102 posts

Uber Geek

#2988575 27-Oct-2022 09:41

timmmay:

2) Make sure you get an Airtouch5 or similar. I wouldn't touch a ducted system without per-room temperature control.

3) This would work if you had an Airtouch or similar. Without an Airtouch, maybe.

I am going to disagree with Timmmay here. We have a ducted system that has a simple damper switch for the bedrooms. If you want the Rolls Royce experience then Airtouch will offer much more flexibility. However if you are aiming for a temperature range, then you will likely find you can deal with problems using simple manual damper switches and closing the duct opening and save yourself 5k. We run ours with a thermostat of 17 in the hallway (where the thermostat controller is) and that equates to a range of 19-21 degrees in every room. Its about learning what your thermostat temp does for your rooms, and setting it accordingly.

The only limitation (and where air touch will work better) is if all of the bedrooms are closed and your thermostat is like ours in the hallway. This is a non issue for us as the kids bedrooms are open. Alternatively you could have the thermostat in a room that actually has a duct, so holds a temp.

In regards to the warm room, if you have the damper close switch you can just stop the air flow to that room.

The other great thing is summers sorted. Nothing better than cool temps for sleeping when everyone else is complaining about how hot, humid and disrupted their sleep was.

timmmay

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#2988584 27-Oct-2022 10:18

I suspect whether Airtouch is necessary depends on your house and how you use it. We had a Panasonic ducted system without zones first, it was awful. The system was really loud, and temperature control was really difficult. I found myself up in the ceiling multiple times per day changing dampers to cater for one bedroom that got super warm from the sun some days, cloudy days it was ok. Having a damper switch per room / zone might be sufficient, but having the electric dampers adds some cost to the system - not sure how much. The Airtouch cost me about $3K from memory, installed with the ducted heat pump, it costs more to retrofit. Before installation I was looking at simple switches and electric dampers, a custom solution, and it was going to cost at least $1K. If a ducted system has basic zoning built in that might be ok, you adjust your manual dampers to balance the rooms. That won't work well if one or two rooms get very warm from the sun some days.

For me, I wouldn't have a ducted system without an Airtouch or similar. Others will vary. Unfortunately it's a decision best made before installation.

stoffel

18 posts

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#2989864 31-Oct-2022 10:00

Thanks for the replies. Gives me something to go on other than just what the installers tell me

Adama64

1 post

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#2996107 14-Nov-2022 17:47

Perkynana:
I have a daikin split system. Been in for 5 yrs. The smaller unit in downstairs bedroom, larger one upstairs. Our house split level 2 story. $5400 installed inc gst

Super Multi NX complete system of:
1 x Outdoor unit Model 4MXM68RVMA
1 x Indooe unit Model CTXM25RVMA
1 x Indoor unit Model CTXM50RVMA

works well. I can’t believe how cheap it is to run. Only negative is I’m a light sleeper and I find noise in bedroom a bit off putting if I leave on all night. However I’m Auckland so doesn’t get that cold so I rarely use overnight.

Can you run 1 room heating or cooling and another room in fan mode
I have same system with 4 indoor . The problem is when upper level room run cooling downstairs room can use as fan mode

Perkynana

23 posts

Geek

#2996117 14-Nov-2022 18:12

I have never tried to run different modes in different rooms. It’s not something I need in our house. I know daikin has a priority room setting where you can set the mode that takes priority over other rooms but I think you will find that if you set the mode in other rooms to something different to the priority room…then the units just sit in standby until the priority room operation is finished.

Maybe google Daikin priority room operation or something as I’ve never used this function but remember reading it in the operational manual.

I think you can only run Cool, dry or fan at same time across the system. So I guess to answer your question it looks like you can run cooling and fan but not heating and fan

im sure an expert with more knowledge will chime in if I’ve got this wrong

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