Source: Chris Potter.

If you're buying a house, you should get a professional home inspection. Its just that simple. Do it.

These professionals have the tools, knowledge, and experience to guarantee there aren't any unexpected or expensive surprises for you and your family after you move in.

There is one small problem, however. The home inspection occurs after you have already made an offer to buy the house, and it can cost you a few hundred dollars in non-refundable cash.

Save yourself the headache and expense by checking these seven problem spots first.

A leaking roof = an expensive roof.

1. The roof
As you approach the house, make sure to take a good look at the roof. Check for consistency on the shingles and to see any obvious sagging in the structure. Replacing a roof is an expensive and highly annoying operation -- save yourself from that nightmare by thoroughly inspecting it up front.

2. The heating and air conditioning
While you are touring the home, ask if you can turn on both the heat and air conditioner. Find a vent and feel the temperature of the air. If you turn on the heat and cold air continues to blow, that's a problem. Go a step further as well and inspect the HVAC unit itself. Most units have a lifespan of 10-15 years, so be wary of older units. Replacing the entire unit can cost several thousand dollars; even replacing a compressor can put you back over a thousand alone. With those kind of dollars on the line, it pays to make sure the HVAC is squared away up front.

3. Under the house
For many of you, the idea of getting onto your hands and knees and squirming into the crawlspace below the house is probably off-putting. The inspector you'll eventually hire will certainly do this, but its worthwhile for you to do it as well. The crawlspace is a very common problem area in many homes -- it is often home to water damage, foundation problems, and sometimes mold or fungus.  

A dry crawlspace is a happy crawlspace.

There are a few problems that exist in homes that should cause you to run, not walk, away from the deal. Many of those problems exist in the crawlspace. Its worth it to put on a pair of overalls and check for water damage, sagging floor joists, or mold. The inspector should find this damage later on, but you can save yourself a few hundred dollars by finding it yourself first.

4. Review historic utility bills
The quickest and simplest way to evaluate a home's energy efficiency is to view historic utility bills. If the insulation is inadequate or the windows are in need of replacing, these bills can let you know of the problem without any knowledge of home construction. In peak seasons, the cost of heating and A/C can be expensive and dramatically impact the affordability of a home. Make sure you understand your monthly energy expenses; they must be paid just the same as the mortgage, insurance, and property taxes. 

5. Check on the property tax bill
Speaking of expenses, make sure to check the tax bill for the property. Depending on the county, city, or neighborhood, the tax rate may be considerably higher than another property just down the road. If the tax assessed value of the property is markedly different than the market value, its possible to request an updated value from the county or city that could reduce the tax burden. However, this process can take time, and you could be obliged to pay the steep tax bill before the tax assessor updates the value. If the location is just right, this may be acceptable; just make sure you understand beforehand all the expenses you will be paying monthly.

Source: DIY Network.

6. Look in the attic
Like the crawlspace, the attic is a critical and often overlooked area of the house. Check the insulation; there should be 6-12 inches of fiberglass insulation, with six inches in more moderate climates and more in colder environments. The attic should be dry, and there should be no visible damage to any of the trusses. Sagging, cracking, or rot are obvious bad signs. 

7. Check the plumbing
This is particularly important for older, existing homes as plumbing systems installed years or decades ago could have significant and expensive damage. Check under the kitchen cabinets and sink and all around the bathroom sink, tub, and toilet. Check that the faucet's hot water works and ensure that the water heater isn't too old, rusted, or otherwise in disrepair. Its also worth it to taste a swallow of water from the faucet; even in areas with high-quality treated water, the pipes in the home may be corroded and tainting the water. A quick taste test will go a long way, and it's free!

Buying a home is a major purchase. A lot of money is on the line, in addition to the comfort, stability, and lifestyle of you and your family. You should always, without exception, hire a professional home inspector to provide you with a report before closing on your home. 

But before you even make an offer, you should personally check these places. In the best case, you'll love the home even more, and in the worst case, you'll save yourself a few hundred dollars and several weeks of wasted house hunting time.