New build - pricing tips

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Blurtie

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#318177 23-Dec-2024 14:49

Hi all,

We're in the final design stages of our rebuild - plans are practically ready for BC application but we haven't pulled the trigger yet. We got some pricing back from the builder and it seems reasonable enough - bar a few minor things we've gone back for clarification on.

As part of the estimate they provided costs for a single heat pump (which I'd like to change to a full ducted HP) and solar system set up amongst other things - which got me thinking if there's any good reason why one would have them include it in the build price? I know you can get things like solar and full ducted systems installed post build by specialist installers.. so my question here is (apart from the obvious ease of installation/coordination during the build by our builder) is there any other reason to get things like this include in the build costs? Part of the costs provided by the builder includes P&G and a margin on top, so I guess we would 'save' this if we were to use a specialist installer for these systems - but is it even worth the effort here?

Would involve a bit of coordinating between builder, PM and installers if we got the builder to pull those costs. Not sure if it's worth the hassle? Are there any other items I should look into and question? Already know about PC Sums and trying to get the builder to lock those in.

Then there's also things like appliances the build has costed that I could probably source my self and save but is that being too nit picky?

Appreciate that the builder or PM would be our first point of contact - but just doing my bit first before going to them.

Would be interested to hear from those that have build recently and whether you just went with your builder for these or used separate specialist installers.. also would welcome any other tips/tricks I can use to bring costs down...

TIA.

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#3323689 23-Dec-2024 14:56

heat pump and solar you would want to run at least the cabling at time of build so save cutting holes in walls, ceilings, roofs etc later on, its also way easier to do it without the lining on.

tweake

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#3323690 23-Dec-2024 15:03

things like appliances, builders often (or at least used to) get discounts. so you may not save anything.

the thing is dislike is having to retrofit stuff. far easier to have it all built in as its built. however builders will often use the cheapest installer who does it the worse. years ago most of my work on new builds was fixing other peoples bad installs, yet i rarely even did installs on new builds. i even had a sparky tell the customer to get a pro to fix his own work.

also its all about having the house designed around those things. single heatpump is a joke. putting ducts in mean you need space to do that, even for cables and pipes. also its a whole lot better if you have a hot roof design (so the attic is basically a normal room inside the house).

Goosey

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#3323696 23-Dec-2024 15:28

If you don’t have the funds right now then pre plan by getting the specs for what you want and have it done

pre wire
pre conduit /holes (Remember a ducted system will need a drain hose… so do standard heat pumps)
allow for solar capable hot water tank and solar capable switchboard and meter areas

I’d be adding a couple power point locations in the roof space too (also a light in the attic would be handy too).

handy to have those power points in the roof space for said ducted system and or otherwise.

many people pre wire security systems and IP cameras. I do hope you are running Ethernet everywhere and not just relying on wifi (and if relying on wifi, then hopefully you are installing sufficient Ethernet at each ends of the property to help with installation of access points).

timmmay

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#3323702 23-Dec-2024 15:43

Ducted heating should be done by an experienced specialist - many of the companies doing it are not very good at it. You really need per-room temperature control with an Airtouch unit or similar, otherwise you end up with some rooms too hot, some too cold. Have a look at the thread I wrote about ducted systems.

The key reasons to do ducting during build time would be:

So the ducts can be run within the insulated envelope of the house, rather than in the ceiling which is hot in summer and cold in winter. i.e. above the ceiling but below the insulation. This is probably a significant change and may not be practical.
You can have your conditioned air pushed in at ceiling level but have the return grill(s) at ground level so that the air is drawn across the room rather than simply heating / cooling the ceiling. Noting you need a 300 - 400mm duct for return, so finding space to do this later is often difficult to impossible.

mattwnz

20164 posts

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#3323705 23-Dec-2024 15:57

timmmay:

So the ducts can be run within the insulated envelope of the house, rather than in the ceiling which is hot in summer and cold in winter. i.e. above the ceiling but below the insulation. This is probably a significant change and may not be practical.

I am not sure how many actually do this, and aren't the ducts insulated anyway? It is normal practice for a conventional house in NZ for insulation to be just above the ceiling lining.. If the insulation is in the rafters, that could add a lot to the cost of the insulation install and it could also mean heat loss from the rooms into the roof space.

I do wonder how effective and efficient ducted is, compared to multi unit heat pumps. We have multiple internal units with a single outdoor unit and find it good and effective

lxsw20

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#3323706 23-Dec-2024 16:03

Trusses need to be designed so there is place for a ducted heat pump so thats something you need to consider before getting plans finalised. You also want to put a decent size man hole in (possibly with ladder).

Appliances we found were cheaper through Harvey Norman and it means we can put them on long term interest free rather than paying mortgage rates on them - we've gone for a mixture of Bosch Series 6 and F&P.

Driveway was about half the price through a 3rd party than through the build company.

I see you've said rebuild, but if you have any mortgage, see if you can put things like the heatpump/windows on the healthy homes 1% loan that some banks do.

Blurtie

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#3323709 23-Dec-2024 16:11

Thanks for all the responses so far.

Guess another way to rephrase my question for those have have gone through the new build process is - what were the essential things you had in the build contract and how much (and what) of the build did you 'outsource'?

For the comments re ducted heat pump - intention here would be to send the plans round to some installers (any recommendations for Chch firms welcome) and get them to coordinate the install through our PM and/or builder at the time of the build rather than post build completely - which hopefully shouldn't be an issue? I assume this what the builder is doing anyway but gets to build it into his costs for P&G and margin..

Only other thing I can think of is warranty/defects - guess if we outsourced it to individual installers we would go to them directly, whereas if it was all done via the builder it would be with them in the first instance?

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mattwnz

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#3323711 23-Dec-2024 16:13

IANAL I would get legal advice before signing any contract. I think you would want to make sure it is a fixed price contract so there is no way the price can be increased. You want to make sure you don't make variations as that is where the costs escalate. So plan plan plan everything now. The issue with buying components yourself is if they are faulty or wrong, you may have to pay additional install costs to get things redone. Likewise if it develops a defect. Make sure you get the warranties or proof of purchase for items purchased off the builder so if you have an issue you can go to the retailer or manufacturer If they disappear or go out of business, or refuse to help, you could be stuck.

tweake

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#3323723 23-Dec-2024 16:53

mattwnz:

I am not sure how many actually do this, and aren't the ducts insulated anyway? It is normal practice for a conventional house in NZ for insulation to be just above the ceiling lining.. If the insulation is in the rafters, that could add a lot to the cost of the insulation install and it could also mean heat loss from the rooms into the roof space.

I do wonder how effective and efficient ducted is, compared to multi unit heat pumps. We have multiple internal units with a single outdoor unit and find it good and effective

this is a big subject worthy of its own conversation.

very few actually do it, but its becoming more of a thing as they push for higher efficiency (mostly overseas). ducts are generally low insulation (which is really just there to stop condensation) and the big thing is duct leakage which causes a few problems. multiple heat pumps is probably more efficient (multi head is less so) but there is downsides to that to.

heat loss to an insulated roof space is not a bad thing. however it does add to the amount of space that needs to be conditioned. on the plus side all that space makes for great storage as its all conditioned. the cost of insulation is a tad extra but really nothing in the scheme of things. the real cost is making the roof line the air barrier instead of the ceiling. that means sheathing the roof and tieing that into the wall so its all air tight. or gibbing under the insulation (like any cathedral ceiling).

nz actually has an excellent opportunity to jump ahead in the learning curve and design houses around whole home heating/cooling.

timmmay

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#3323724 23-Dec-2024 16:55

mattwnz:

I am not sure how many actually do this, and aren't the ducts insulated anyway? It is normal practice for a conventional house in NZ for insulation to be just above the ceiling lining.. If the insulation is in the rafters, that could add a lot to the cost of the insulation install and it could also mean heat loss from the rooms into the roof space.

I do wonder how effective and efficient ducted is, compared to multi unit heat pumps. We have multiple internal units with a single outdoor unit and find it good and effective

It's not normal in NZ, but it's normal in colder countries - though I have have the details wrong. You wouldn't want to insulate right under the ceiling, I guess you kindof need an intermediate area between the ceiling you can see from inside the house and the insulation. I'm not sure how practical it is.

Ducted heat pump ducts are usually R0.6, or you can upgrade to R1.0, which is not much insulation - in practice 2-3cm thick around the duct.

Ducted is less efficient that highwall units where the whole indoor part of the heat pump is inside the insulated envelope. Ducted is quieter, is usually considered less ugly, but it's also much more complex and much more difficult to do well. I don't know if I'd bother doing it again, if you can tolerate high wall or floor units that is simpler.

tweake

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#3323732 23-Dec-2024 17:17

timmmay:

It's not normal in NZ, but it's normal in colder countries - though I have have the details wrong. You wouldn't want to insulate right under the ceiling, I guess you kindof need an intermediate area between the ceiling you can see from inside the house and the insulation. I'm not sure how practical it is.

its not normal even in colder climates (using USA as an example, europe does things different but they also don't use a lot of ducted systems afaik). its relatively new especially as usa keeps pushing for more efficient houses. the joe blog usa house still runs ducts under the floor or in the ceiling outside of the insulation. they are leaning its better to put it all inside the envelope, something we could do without having the many many decades of putting ducts in ceilings.

the insulation goes right under the roof, just like any normal cathedral ceiling that many many nz homes have. basically the whole house has cathedral ceiling, even tho it also has a normal flat ceiling as well.

Handle9

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#3323806 23-Dec-2024 19:17

The reason to include things like heating in the build contract is it provides clear responsibilty and leaves the coordination headaches with the builder. If the builder hasn't sized the trusses for the ducted unit it's their problem to fix. If the installer cuts a hole in the ceiling in the wrong place and there is repair work required it's the builders problem to fix. He is responsible for coordination and project management and any delays or coordination problems are in his scope.

If you descope it then it's your problem. If the builder has to wait for your contractor he can claim a variation if he incurs costs, if something goes wrong in the DLP then you have to deal with the inevitable blaming of the your contractors by the builder.

If you have the skills and the time you can save quite a lot of money but if you don't then pay the margin and save the headache. The hardest part of building is managing risk. That's why you pay the builder a margin so he can do that for you.

Handle9

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#3323807 23-Dec-2024 19:20

lxsw20:
Appliances we found were cheaper through Harvey Norman and it means we can put them on long term interest free rather than paying mortgage rates on them - we've gone for a mixture of Bosch Series 6 and F&P.

Driveway was about half the price through a 3rd party than through the build company.

This is exactly the sort of stuff that makes sense to sort out yourself. There are really no dependencies or coordination problems so it's a great way to save some money.

Handle9

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#3323808 23-Dec-2024 19:25

tweake:
the insulation goes right under the roof, just like any normal cathedral ceiling that many many nz homes have. basically the whole house has cathedral ceiling, even tho it also has a normal flat ceiling as well.

If you are going to do this get someone to actually give you some calculations showing what you will save.

You're making a ton of decisions and the difference can only be a few hundred or thousand dollars for each one but pretty quickly you have raised the build cost by 50k with a 10 year payback (if interest rates stay low.)

Make your house as efficient as you are comfortable with but it's all a compromise between running costs and build costs. At least be informed what impact each change you are making will make so you can put your money in areas that have the most impact on your lifestyle.

Things like heatpump water heaters are a classic way to over invest when often it doesn't make much sense.You can also often make it realtively easy to change in the future as the economics of these types of plant change.

timmmay

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#3323826 23-Dec-2024 20:20

tweake:

its not normal even in colder climates (using USA as an example, europe does things different but they also don't use a lot of ducted systems afaik). its relatively new especially as usa keeps pushing for more efficient houses. the joe blog usa house still runs ducts under the floor or in the ceiling outside of the insulation. they are leaning its better to put it all inside the envelope, something we could do without having the many many decades of putting ducts in ceilings.

the insulation goes right under the roof, just like any normal cathedral ceiling that many many nz homes have. basically the whole house has cathedral ceiling, even tho it also has a normal flat ceiling as well.

Ah ok. I watched quite a few videos from the US when I was getting my ducted system installed, they made it sound like it was normal. It would add a lot of area to be heated if the insulation is way up near the roof, it doesn't sound worthwhile. I wonder how it's done in the states, maybe a false ceiling or something, but I guess it'd have to be pretty extreme weather to be worth it.

My other thought, on a floor level return vent, may still be worthwhile. Or just avoid the ducted system.

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