When designing a new home, some simple upgrades can improve its performance. These go beyond the minimums required by the New Zealand Building Code and can help to:
- keep temperatures more comfortable for longer
- use fewer resources such as energy and water
- make it cheaper to run.
How to use
1. Confirm the budget with your client.
2. Determine the theme(s) you and your client want to address:
3. Pick the desired features with your client, up to the budget.
4. Develop an accurate quote.
The following improvements will help make the house more comfortable while needing less heating or cooling over the year, therefore saving on energy costs. (Note that an accurate ‘yearly savings' figure cannot be determined by adding two or more thermal improvements together.)
|THERMAL improvement||extra cost||yearly savings||thermal benefit|
|Living areas facing north, garage facing south||Marginal||$50||Good|
|NZ Building Code H1 solution (R2.9) is the most cost-effective solution while cheap electricity is available||NA||NA||NA|
|Standard, aluminium-framed double glazing is the most cost-effective solution, while cheap electricity is available||NA||NA||NA|
|Standard concrete slab|
|Living areas have exposed concrete slab (i.e. polished), with all other areas carpeted||$700||$100||Good|
|Living areas have exposed concrete slab (with finish), other areas tiles||-$2,200 (savings)||$110||Very good|
|50 mm expanded polystyrene insulation under concrete slab + exposed slab in living areas, otherwise carpeted||$2,800||$210||Very good|
The extra cost refers to the costs over and above what a more standard component or system would typically cost to purchase initially. The yearly savings are a result of the lower need for space conditioning energy use only. Figures are based on the needs of typical spec homes.
The following improvements will help make the house cheaper to run. (Individual improvements can be added together to provide combined extra costs and yearly savings.)
|ENERGY improvement||extra cost||yearly savings|
|Photovoltaic-ready house (installing cabling only)||$400||NA||NA|
|3 kWh grid-connected photovoltaic system fully installed||$10,000||(see note 1)||(see note 1)|
|Appliances and lighting|
|Correctly-sized heat pump||$0||$50||Good|
|4 Energy Star fridge-freezer (380 litres)||$100||$60||Good|
|All lighting energy efficient (CFL or LED)||$300||$150||Very good|
1. Savings are difficult to determine given the rapid price changes for photovoltaics (PVs) and a number of other factors. See the Photovoltaic (PV) Design fact sheet for more information and further reading.
The extra cost refers to the costs over and above what a more standard component or system would typically cost to purchase initially. The yearly savings is the estimated benefit in lowered energy costs resulting from better appliance efficiencies.
The following improvements will help to manage water resources better. (Individual improvements can be added together to provide combined extra costs and yearly savings.)
|WATER management||extra cost||yearly savings|
|Small fittings and appliances|
|4 star or better WELS2 toilets||Marginal||1,600 litres||Good|
|4 star WELS kitchen and bathroom tapware||Marginal||2,300 litres||Good|
|4.5 star WELS dishwasher and washing machine||$300||19,500 litres||Very good|
|4 star or better showerheads||Marginal||57,100 litres||Excellent|
|Rainwater tank systems|
|1,000 litre water tank with feed pump to garden||$2,400||93,000 litres||Outstanding|
|5,000 litre water tank with feed pump to laundry and WC||$4,700||120,000 litres||Outstanding|
|25,000 litre water tank with feed pump to whole house3||$7,400||138,000 litres||Outstanding|
2. WELS = Water Efficiency Labelling Scheme.
3. Check regulations with local council first.
The extra cost refers to the costs over and above what a more standard component or system would typically cost. The yearly savings is the estimated benefit in terms of saved water over a typical year given typical occupants.
The performance upgrades are based on independent research by BRANZ and are region specific where possible. Only the most cost-effective improvements have been selected, based on homes consented in 2012. The cost and benefit figures are averages derived from actual consented plans and take inflation and returns into account. All figures are estimates and should be seen as starting points for discussions.
Once the upgrades have been chosen, the estimated figures for extra costs will need to be more accurately determined and will vary depending on the specific design.
If you would like the detail on how this was calculated, including the full (unfiltered) list of improvement upgrades considered, see the background document Up-Spec: Background Research
The figures in the regional checklists consider those costs and benefits that are reasonably easy to quantify. Harder to quantify - but that might be even more important to the owner - are the:
- health and comfort benefits from having a warmer, drier home
- improved resilience and self-sufficiency for the home
- Homestar points resulting from the upgrades.
Ideally, these other benefits should also be considered as part of the decision-making process.
We'd like hear from you - please provide feedback via firstname.lastname@example.org