heat pump needs more airflow, so does aircon. real common problem overseas where gas heating is very common.

tweake:

 

heat pump needs more airflow, so does aircon. real common problem overseas where gas heating is very common.

 

a lot to work through , might get some quotes and do the maths on it 

Suggest you find an experienced installer who knows their stuff. High volume doesn't always mean they know anything. Anything you read online take with a grain of salt - especially what I say :)

I suspect heat pumps put out air that's not as hot as gas systems, so you need higher volumes of air. Higher volume of air through a narrow duct means noise, or you may not be able to push enough air through. I think most rooms have 200mm ducts in our ducted system, from memory, 250 to the lounge before it splits, and the return is 300 or 400mm - not sure.

If you asked my wife she'd say she'd never have ducted again. Individual room units do have their advantages, not having to deal with returns or such would be helpful. If I was starting again I'd think hard about whether to do ducted or high wall / floor units. The ducted works fine in most cases, but things like diffusers pushing the air in at the ceiling and the return being at the ceiling doesn't work great, you want to draw air across a room rather than blow it around.

timmmay:

Suggest you find an experienced installer who knows their stuff. High volume doesn't always mean they know anything. Anything you read online take with a grain of salt - especially what I say :)

I suspect heat pumps put out air that's not as hot as gas systems, so you need higher volumes of air. Higher volume of air through a narrow duct means noise, or you may not be able to push enough air through. I think most rooms have 200mm ducts in our ducted system, from memory, 250 to the lounge before it splits, and the return is 300 or 400mm - not sure.

If you asked my wife she'd say she'd never have ducted again. Individual room units do have their advantages, not having to deal with returns or such would be helpful. If I was starting again I'd think hard about whether to do ducted or high wall / floor units. The ducted works fine in most cases, but things like diffusers pushing the air in at the ceiling and the return being at the ceiling doesn't work great, you want to draw air across a room rather than blow it around.

timmmay:

 

If you asked my wife she'd say she'd never have ducted again. Individual room units do have their advantages, not having to deal with returns or such would be helpful. If I was starting again I'd think hard about whether to do ducted or high wall / floor units. The ducted works fine in most cases, but things like diffusers pushing the air in at the ceiling and the return being at the ceiling doesn't work great, you want to draw air across a room rather than blow it around.

 

i think half the problems are that our homes are not designed for ducted systems. having equipment and ducts outside is poor. even just getting space for it all. plus kiwis are so used to heating per room rather than whole house. but on the other hand people do like different temps and often like to sleep at a lower temp.

tweake:

timmmay:

If you asked my wife she'd say she'd never have ducted again. Individual room units do have their advantages, not having to deal with returns or such would be helpful. If I was starting again I'd think hard about whether to do ducted or high wall / floor units. The ducted works fine in most cases, but things like diffusers pushing the air in at the ceiling and the return being at the ceiling doesn't work great, you want to draw air across a room rather than blow it around.

i think half the problems are that our homes are not designed for ducted systems. having equipment and ducts outside is poor. even just getting space for it all. plus kiwis are so used to heating per room rather than whole house. but on the other hand people do like different temps and often like to sleep at a lower temp.

Stu1:
Radiators would be great option but just have the wall space in the kids rooms , quite a compact typical 70s house . The write up you did is fantastic. I will get a couple of heat pump installers out for options as well as central heating to look at cost for a bigger unit. It’s the cooling side that attracts me to the heatpump option it’s just soo hot even with decent double glazing. I ended up getting a retractable awing for my daughter’s room often hit 30 inside her room . I might just look at a couple more for the other 2 bedrooms. They are great on a still day not so good when it’s windy . Either way I have to look at option for heating the existing gas unit isn’t big enough or zoned it’s working harder to maintain temp and of course chewing through the gas .

My son's room would hit 30 if we didn't actively cool it. Some days we have to cool that room and then turn the heating on for the rest of the house. Our first ducted unit without per room thermostats it was awful, the south side of the house ended up super cold and the north side still too hot.

timmmay:

Stu1:
Radiators would be great option but just have the wall space in the kids rooms , quite a compact typical 70s house . The write up you did is fantastic. I will get a couple of heat pump installers out for options as well as central heating to look at cost for a bigger unit. It’s the cooling side that attracts me to the heatpump option it’s just soo hot even with decent double glazing. I ended up getting a retractable awing for my daughter’s room often hit 30 inside her room . I might just look at a couple more for the other 2 bedrooms. They are great on a still day not so good when it’s windy . Either way I have to look at option for heating the existing gas unit isn’t big enough or zoned it’s working harder to maintain temp and of course chewing through the gas .

My son's room would hit 30 if we didn't actively cool it. Some days we have to cool that room and then turn the heating on for the rest of the house. Our first ducted unit without per room thermostats it was awful, the south side of the house ended up super cold and the north side still too hot.

Stu1:

Is there anyway to reuse gas central heating ducting with a central heating heat pump system

Stu1:

 

Is there anyway to reuse gas central heating ducting with a central heating heat pump system? 

 

We got two quotes for installing heat pumps into our new house, and the answer from both companies was "no". 

(We still haven't installed any heat pumps.) 

timmmay: Congratulations! Everyone's house is different, asking for advice makes sense.

I think that's a non sequitur, if everyone's house is different wouldn't that lead to a bunch of completely different, house-specific responses to the question?

cddt:

Stu1:

Is there anyway to reuse gas central heating ducting with a central heating heat pump system? 

 

We got two quotes for installing heat pumps into our new house, and the answer from both companies was "no". 

(We still haven't installed any heat pumps.) 

jonathan18: 

My in-laws did this in their house a number of years ago when the gas-powered central heating system cr@pped out soon after they moved in. It seems to work well; in particular, I prefer the air coming from the ground level rather than the ceiling as it does in our set-up.

Obviously lots of different variables are in play so it may not work in your situation, but I’d certainly say it’s worth checking out more fully.

they could have had an oversized gas system and fitted an undersized heatpump. or they added outlets etc. or its actually not very good and they just don't notice. always take the outliers with a grain of salt.

tweake:

timmmay:

If you asked my wife she'd say she'd never have ducted again. Individual room units do have their advantages, not having to deal with returns or such would be helpful. If I was starting again I'd think hard about whether to do ducted or high wall / floor units. The ducted works fine in most cases, but things like diffusers pushing the air in at the ceiling and the return being at the ceiling doesn't work great, you want to draw air across a room rather than blow it around.

i think half the problems are that our homes are not designed for ducted systems. having equipment and ducts outside is poor. even just getting space for it all. plus kiwis are so used to heating per room rather than whole house. but on the other hand people do like different temps and often like to sleep at a lower temp.

timmmay:

 

Suggest you find an experienced installer who knows their stuff. High volume doesn't always mean they know anything. Anything you read online take with a grain of salt - especially what I say :)

 

I suspect heat pumps put out air that's not as hot as gas systems, so you need higher volumes of air. Higher volume of air through a narrow duct means noise, or you may not be able to push enough air through. I think most rooms have 200mm ducts in our ducted system, from memory, 250 to the lounge before it splits, and the return is 300 or 400mm - not sure.

 

If you asked my wife she'd say she'd never have ducted again. Individual room units do have their advantages, not having to deal with returns or such would be helpful. If I was starting again I'd think hard about whether to do ducted or high wall / floor units. The ducted works fine in most cases, but things like diffusers pushing the air in at the ceiling and the return being at the ceiling doesn't work great, you want to draw air across a room rather than blow it around.

 

Apologies for resurrecting an old post but I've sat on this for months and done nothing about it due to indecision! But now, my existing sole 9kW heat pump has packed up and is being replaced by a shiny new Mitsubishi Electric AP80 9kW unit so it has encouraged me to sort this out once and for all.

timmmay has managed to talk me out of going for a ducted system, just seems too complicated with too many variables and too much reliance of finding a good installer. So I'm looking at installing a Mitsubishi Electric multiroom system with 5 indoor units (in 3 bedrooms, kitchen/diner and study), (3 x AP25 3,2kW & 2 x AP35 3.7kW) connected to a 5F100 10kW outdoor unit. I've been advised that this will be enough as only a couple of the indoor units would ever be on at the same time.

So my question to those a lot more knowledgeable than me, does this seem like a reasonable solution to avoid a ducted system? I've been quoted $10,650 installed which is a combination of lower prices on the indoor units and price matching the outdoor unit. Does this sound reasonable? Many thanks.