Hello from N.Ire - new build planning

[StevieD]

Hello there,

 

Finally embarking on building our family home. We have recently received our outline planning permission and are now in the middle of detailing our plans for the house and site. Thankfully we have only been given a few restrictions to work around but doesn't really affect our home. We intend to carry out some civil work ourselves (clear and elevate site, foundations, stw, fw and some shoring & eventually landscaping w/fencing). Depending on the quotes, we were thinking of building a specification and letting out a contract to a local builder.  I find there will be many pros/cons over complete self build vs managing a contractor on limited works (time vs cost vs quality paradigm).

 

There are still a few options we are still at odds to decide on and I was hoping for some guidance on;

 

• Heating /hot water options - we are keen to move away from oil and gas heating and more towards renewables/energy efficient options. Reading through a few topics on this forum, it seems something like an ASHP would be best suited for a new build for a, best outlay of cost and returns b, it can be installed with the best materials for best efficiency of the system i.e. UFH heating with concrete floors, insulation, air tightness. I have by no means even a mediocre understanding of heating systems but would ASHP supplying UFH and solar panels aiding the hot water supply be the most energy efficient & low cost option for a new build? I am prepared to have a bigger outlay installing something that will have a lower maintenance/running cost over 20-30 years. In each of the living  rooms, we will have a wood burner.
• Being from NI, are there any grants available for self/new builds. I believe there had been one for solar panels but it no longer exists. NI's version of the RHI is under somewhat intense scrutiny but I don't think there are options there. I cant seem to see any other incentives out there but if anyone can provide directions to any, it would be much appreciated.
• With the world currently on a climate change push to being more carbon neutral and forever sustainable, should there be anything to consider pre-emptively i.e. electric car charging port in garage (I have set out to buy an electric car in approx. 5 years time as it will inevitably be the way to go).
• This may be a complete folly but what would it cost for a rural home to be powered off grid, for example - a bank of solar panels charging a battery pack (10kw/20kw?) which then supplies the house. Its possible but probably expensive. I have seen some solutions but haven't scaled it to suit a 2 storey (approx. 250m2) house with double garage and shed. 

 

Some information on my little corner of the world.

• Its a half acre site (approx.50m x 35m tapering to one side) with the east side facing a road. Lined with mature trees (a restriction has ordered one to be felled but I would like to fight this and move the access lane slightly to avoid). We also have the half acre field to the north too.
• I intend to split the site in to thirds, south 1/3 for the garden, middle for the house, and north section for the garage (intend to have a double housed garage and an additional one open bay)
• The house is currently approx. 250m2 but plans are yet to be finalised, I've added my sketch below for info. Still mulling over the sizes of the rooms. (I couldn't rotate to be in line with the plot image).

 

Any advice would be much appreciated

 

[Declan52]

Welcome Stevie. 

The biggest issue you will have here is finding an installer who knows what they are at in terms of installation of your ashp and then setting it up correctly. There is a self build show in Belfast next weekend at the Titanic building and that will be your best bet to visit all the many different companies who do this work. You can also look at all the other different materials that you will need. Most of the lenders offering finance will be there as well.

As far as solar panels go the grants have finished so you just do a self install where you try to use all the electric you generate. Your only really generating from April to October then it justs drops of a cliff. 

Once you are ready to start you need to get on the ball with powerni, ni water, bt etc as they are slow to deal with.

[StevieD]

Hi Declan

We have booked ourselves in for the Self build show, we attended it last year as a first venture. This year we are more focused on what we want to see and have a set list as opposed to meandering through all the stalls. Some we just wont be interested in but we will make a day of it.

Our local plumber raved about the ASHP as he had fitted it to his house last year and highly recommends it.

Thankfully we are close to the road so connections shouldn't be much of an issue, as you say slow to work with. In an ideal world I would love to live the good life and be completely off grid bar internet connection.

[Declan52]

I have an electric pole in one corner of my site but it still took a year to sort out.

We visited the show about 4 times and each visit we asked more and more questions as we knew more and more about each aspect. Collect all the fliers you can and then when you have the time you can go through them and pick a few out.

 

[StevieD]

Thanks I will do, I find the problem with a self build is there is too much choice and decisions to consider for your home!

 

What's your take on the best method for home heating and hot water supply? One of the great things is its a chance to have a good efficient and economical system. I have stayed in some houses where ive had the oil auger going flat out with two open fires in the winter time as the system was very inefficient and had poor insulation. Id like to get it right first time.

[Declan52]

It's all about the details. You need to put that much insulation in the walls, floor roof, gd quality Windows and doors and have your house airtight that heating isn't really that much of an issue. It's more how you solve your dhw supply.

You can go for an ashp and run it at low temp to provide the ufh which will heat your house. But you need to have done all the work before hand so it can provide enough heat without it leaking out through the floor and walls etc.

How does your plumber work his???

[Conor]

Welcome Stevie. Where abouts are you?

 

ASHP does seem to be the best option. But your focus should be on the overall air tightness and insulation of the building. That's the best way to ensure low running costs and environmental impact. The current building regs aren't the best and you should be aiming above.

We're aiming for passive standards, i.e. wall u values of less than 0.15, triple glazed windows throughout, MVHR, solar PV and good airtightness. All of that means that the heating demand of our 290m² house will be so low, we will only need a small 5kw monoblock ASHP.

 

FYI you won't have an open fire in the new house, but get a room sealed multi fueled stove somewhere in the house. You won't use it much, but worth having.

 

When you're at the show, speak to Daly renewables re ASHP and Graeme from Green Energy Store re solar and off grid options.

 

Unfortunately there are no grants of any type!

[StevieD]

Thanks for the information, my brother has under floor heating and the big issue he had was the guy installing it forgot to pressure test it, so after it was installed (and tiled over...) ran the heating and voila, upstairs leak, took up 10ft of flooring before it was located.

 

I'm all for over insulating the house,  just need to get my head around developing the spec. We will have quite a few windows so the insulating and sealing around them will be important. Is domestic cavity still tend to be 2 inch board and 4 inch blockwork or upgrade to thermal blockwork? Pre -cast first floor slabs?

For DHW I'm mirroring the downstairs b'room with upstairs and master en-site will be above utility room. She wants a zip hot water for the kitchen so should only be a cold feed for there. Trying to keep the amount of runs and chasing to a minimum.  I haven't had any costings yet, but what would a ASHP with UFH for 250m2 roughly cost?

 

BTW - if you haven't met my wife, she would want the stove on, even if she was sitting in the Australian outback during summer.... We are based in mid-ulster between the sausages and the chickens...

 

I will definitely look out for Daly and Green Energy thanks. As I said, you would need a spreadsheet of the different systems, combinations of primary and secondary, cost of running vs install, etc.