House prices are high in many urban centres, but the costs of owning homes has gone through the roof too.

Figures from Statistics New Zealand show general inflation was 19.8 per cent since Mid-2006, but the costs of ownership have risen far faster, with maintenance costs alone having gone up by nearly 35 per cent.

Insurance and rates having outstripped inflation by a large margin too.

But these costs don't appear to be reflected in the prices many buyers are willing to pay.

In a boom, where buyers vastly outnumber sellers and capital gains are the name of the game, and experts feel that buyers are not factoring in the state of homes, and the likely costs of keeping them in good nick into the prices they pay.

That's encouraged one homeowners' group to develop the equivalent of the AA car check, but for homes.

Hobanz, the Homeowners and Buyers Association of New Zealand, would like to be the AA of homeowners.

To date, Hobanz has made headlines for its involvement in helping leaky building owners fight for funds to fix their properties, but its chief executive Roger Levie plans to turn us into a nation of more discerning home buyers just as the AA has helped make us better car buyers.

The aim of the home check service, which is under development, was to help the owner work out the true value of a property taking into account the state of the home, Levie said.

Just as the AA checks will identify work that needs doing, so Hobanz' planned home check would give prospective buyers a better understanding of the costs they are likely to face as owners.

The idea isn't however to get the buyer to pay, as is the case with AA car checks.

"Our approach is to get the vendor to put the report in place because he has much more access to the property," Levie said. "It is a good thing for the vendor to understand the state of the property they are selling."

Levie said New Zealand had built large, high maintenance homes.

Weatherboard houses need regular painting, but that's nothing to the care that has to be lavished on houses skinned with cladding.

Levie said many homeowners had little understanding of how to maintain their homes, especially clad homes, and making matters worse was the poor quality of workmanship on many.

Levie said: "The smart thing to do is to have your own maintenance plan."

But that is easier said than done.

It is not even common for people buying new homes to have files on their homes which detail the materials they are made with and the warranties that cover their homes, Levie said.

The high prices people are paying for homes also leaves little to set aside for future maintenance.

"What we do spend is hardly anything," Levie said. "It is a really big issue for New Zealand. A lot of our homes are under maintained."

"It's not really been factored into the price of properties," he said.

Knowing what you should be spending on maintaining a home is tough.

Andrew King from the New Zealand Property Investors' Federation said there were some landlord rules of thumb based around setting aside a portion of the rental income.

"For a simple, two bedroom, brick and tile unit, you are probably talking about 5 per cent. For an old villa, maybe 10 per cent."

"If you buy a big old grand place, it is going to cost you more," King said.

With prices so high, and insurance so costly, that's proving tough for landlords.

King said the Federation was surveying landlords, and the main reason being given by those selling properties are that yields have fallen so low.

Other rules of thumb on maintenance have been put forward.

Propertytoolbox.co.nz has suggested "as a bare minimum" $1500 or "better yet" 0.3 - 0.5 per cent of the value of your house per year for maintenance.

The trouble with that is that 0.5 per cent of an Auckland home worth $1million in 2010, and now worth $1.4m, would have jumped from $5000 to $7500.

But King said the true amount that will need to be spent depended on the house.

Figures from Statistics New Zealand show the cost of owning a home can shift dramatically over relatively short periods of time.

And changes of regulation can dramatically lift the cost, depending on the type of home you have.

Earlier this month, the New Zealand Initiative, a right-leaning public policy think tank, published A Matter of Balance: Regulating Safety which claimed that the "falls from height" workplace safety campaign from WorkSafe was adding thousands of dollars to the cost of building new homes and routine maintenance of existing homes.
Dr Oliver Hartwich, executive director of the New Zealand Initiative, said: "A small-scale builder reported that the cost of complying with the WorkSafe New Zealand campaign turns a small $4000 roof job into a $6000 job."

A villa-owner using the landlords' rule of thumb could use the tenancy database to work out what their home would rent for to see what that would mean they might be setting aside.

Someone with a three-bedroom villa in Auckland's Mount Eden, which would rent for $600 a week, should be setting aside $3120 a year for maintenance.

WHAT CPI SAYS WE SPEND ON HOMES

The Consumer Price Index, or CPI, is how we measure the rate of price change of goods and services purchased by households.

But it covers all households, meaning it does not provide an accurate measure of your household's experience of inflation.

It catches the spending patterns of homeowners and renters, rich people and poor people, owners of leaky homes and owners of low-maintenance brick and tile units. It covers meat-eating, alcoholic smokers as well as teetotal vegans.

But CPI also provides an insight into the proportion of household income spent on certain things.

That's because the CPI is based on a basket of goods and services which represents national household expenditure patterns, and these change over time.

The CPI weightings for home-related spending make for disturbing reading for homeowners.

Back in the second quarter of 2006, home maintenance made up 2.24 per cent of the CPI basket of goods and services. In 2015, it is 3.09 per cent.

We are spending more on maintenance, though that doesn't necessarily mean we are doing much more maintenance.

The cost of maintaining a home (paying tradesman and buying materials) is up by 34 per cent over that time, compared to 19.8 per cent for CPI, so it may be fair to conclude that price rises are behind at least part of that.

Other homeowner costs rose too.

Over that time property rates (including the costs of water) rose 61.4 per cent.

Unsurprisingly, the weighting in CPI also rose, indicating that council rates are consuming a larger proportion of household expenditure.

In 2006, the weighting was 2.44 per cent compared to 3.18 per cent now.

Since the Christchurch earthquakes house and contents insurance has also risen.

In 2006, their combined weighting was 5.12 per cent of CPI. Today it is 7.04 per cent. The actual rate of inflation on dwelling insurance was 218.3 per cent, and 44.4 per cent on contents.

The weightings, though they will not reflect the real rise in costs of owning a home, do give an indication that it has got more expensive.