BEFORE YOU BUY THAT HOME, AVOID UTILITY BILL SHOCK

Housing affordability isn't just about your monthly mortgage or rent payment. Utilities can be a stealth budget buster.

Median spending on utilities is $2,715 per year – or $226 per month – for single-family homes, according to a new analysis from real estate website Trulia. Even when you're comparing homes of similar sizes and prices in the same region, it found, energy costs can vary widely based on factors like the local utility providers' rates, the age of your home and the size of the lot it sits on.

"If you're moving to a single-family home for the first time, or moving to a new area in general, this is definitely something you should be paying attention to," said Felipe Chacon, a housing data analyst at Trulia.

(Trulia's analysis used July data from UtilityScore, tallying water, natural gas and electricity rates into a single price per square foot. It also looked at climate data as a predictor of energy bills at the local and metro levels, but per the report, "the correlation was underwhelming.")

For example, homes in Three Points, Arizona, have utility costs 2.5 times as high as those in nearby Avra Valley, Arizona — $620 per month versus $240 — despite the two Tucson suburbs having homes comparable in square footage and value. Much of the difference stems from larger lots in Three Points, said Chacon, which can trigger bigger water bills for maintaining the landscaping.

To avoid a surprise, ask about utilities during your hunt. Real estate listings often include estimates, but it's smart to ask for a copy of recent statements to see real numbers, said Cathy Seeber, a certified financial planner and partner at Wescott Financial Advisory Group in Philadelphia.

"Most give you annual information, so you can see what the historical bills have been," she said.

Don't assume high figures can be solved by say, making home improvements to boost energy efficiency, said Chacon. Look to see how the utility divides the bill — some have a high fixed charge for providing service and lower rates based on usage, limiting your ability to save. Smaller utility companies also often have higher rates because they don't have the same economies of scale that big utilities do, he said.

While you're at it, consider costs and coverage options for other home services like internet, cable or satellite TV, said Seeber — who has seen clients buy a home only to sell it quickly because they couldn't get decent cellphone reception or high-speed internet. Sites like Allconnect.com can help you find providers by address and ZIP code, while Opensignal.com maps wireless coverage. When in doubt, said Seeber, ask the neighbors how they've fared.

If you find utility costs to be bigger than expected in a new place, conduct a home energy audit to locate the trouble spots. The Department of Energy offers guidelines to do the assessment on your own; many state agencies and utilities also offer free or low-cost professional audits.

Some improvements quickly pay for themselves. Sealing air leaks and weather-stripping windows could cut bills by as much as $166 and $83 per year, respectively, according to government estimates, while insulating your water heater tank could save another $45.