This means when you take out a new house insurance policy you’ll now need to specify the amount it would cost to fully rebuild your house. This is called the sum insured, and it’s the maximum your insurance company will pay out if your home is destroyed. It is now your responsibility to ensure this figure is enough to rebuild your home in case of a total loss and to keep this figure up-to-date.

If you have insured your house through Kiwibank, your house insurance cover is provided by Tower Insurance Limited.

How it works

If you’re applying for house insurance

You’ll need to specify a sum insured amount when you apply for your insurance.

Calculating your sum insured

Your sum insured is not the same as your house’s market value. It’s the likely cost of replacing your home on its current site, based on its current:

  • size
  • standard and type of construction
  • structures, like decks, driveways, sheds, garages, retaining walls, fencing and outbuildings
  • period features (typically in villas and bungalows)
  • special features like permanent swimming and spa pools.

This amount needs to include everything it would cost to rebuild your home, including:

  • building material and labour costs
  • demolition and removal of debris
  • site preparation
  • professional fees
  • compliance costs.

To set your sum insured, you can either:

  • get a licensed builder, quantity surveyor, or architect to provide an estimate of what it could cost to rebuild your home
  • ask a registered valuer to value your home for insurance rebuild purposes
  • use the independent Cordell calculator as a guide.

Cordell calculator

The Cordell calculator is an independent tool that generates an estimate of your likely rebuild cost based on the information you provide about your house. It may not be as accurate as a valuation done by a professional.

To complete the calculator, you’ll need to know:

  • the size of your home in square metres
  • when it was built (approximately is fine)
  • what your house is made out of – what the flooring materials are, how it’s clad, what kind of roof you have
  • what other structures you have on your property – e.g. garages, decks or swimming pools
  • the slope of your land and any retaining walls
  • how many levels your home has.

The cost of rebuilding retaining walls and swimming pools are considered, but other features aren’t. The calculator won’t consider features like:

  • jetties and wharves
  • private landings
  • permanent fords or dams
  • bridges and culverts
  • cable cars
  • private utility plants like windmills, watermills or diesel generators.

While the calculator can be useful it does have limitations that you should be aware of. It may not be accurate for very large or high value homes, such as those that cost over $2 million to rebuild, and does not factor in many special features including:

  • areas of shared ownership, such as driveways and fencing that you co–own with neighbours
  • hard to access sections
  • houses with multiple construction materials (e.g. brick and weatherboard)
  • houses with mixed commercial and residential use.

If your home has any of these features you might want to consider getting a professional valuation to ensure you’re adequately covered. If you don’t, you’ll need to add an additional amount to your estimated sum insured to take these features into account.

Use the calculator

Remember to save a copy of your results for your own records.

Shared ownership

  • If you share a driveway or fences with your neighbours, you’ll need to decide what you’ll each insure and for how much.
  • If you live somewhere governed by a body corporate, like an apartment complex, the body corporate usually has one insurance policy covering all the units in the complex, and all the common property. This may already be insured on a sum insured basis – you can find out from your body corporate secretary or committee.

You’ll need to understand the extent of your liability and allow for it in your sum insured.

Keeping your sum insured up to date

>Once you’ve set your sum insured, it’ll be adjusted automatically for building inflation each time your policy renews. It’s still your responsibility to check the sum insured is accurate for your home each year, and adjust it if you make renovations or add new features. Tower recommends you assess this figure each year to make sure it’s right for you, as well as each time you make any renovations or other improvements.

Call one of our insurance experts on 0800 222 491

The Cordell Online Calculator provides factual information as to the estimated rebuild cost of your home, based upon the details that you provide. This calculator provides an estimate only based on industry average building replacement costs and the true replacement cost of your home will vary depending on your circumstances. It does not constitute a recommendation or opinion in relation to taking out or replacing an insurance policy. It is not personalised financial advice. It does not take into account your particular financial situation or goals. The calculator is provided by Cordell Information Pty Ltd and licensed for use on this website. Whilst effort has been made to ensure that the information is accurate, Kiwibank Limited and Tower Insurance Limited accept no responsibility for the accuracy of any information in, or results derived from, or any reliance you place on, the calculator.

House, Contents and Vehicle Insurance are provided by Tower Insurance Limited, and Tower Insurance Limited is solely responsible for any claims under the policy. Kiwibank Limited (including its related companies) does not guarantee the obligations of, or any products provided by, Tower Insurance Limited or its related companies. Kiwibank Limited may receive a commission on any policy it arranges.

Important terms, conditions and exclusions are set out in the House, Contents and Vehicle Insurance Policy wording (PDF 669.2 kB). Effective from 6 December 2016. If your policy was issued before this date, the wording in your policy may differ. Please contact us for a copy of the policy that applies to you.

“We”, “us”, or “our” means Tower Insurance Limited.

Tower Insurance Limited has a financial strength rating of A- (Excellent) as at 15 July 2016 from A.M. Best Company.

Rating Scale


  • A++, A+ Superior
  • A, A- Excellent
  • B++, B+ Good


  • B, B- Fair
  • C++, C+ Marginal
  • C, C- Weak
  • D Poor


  • E Under Supervision
  • F In Liquidation
  • S Suspended