You can ask a realtor for their estimate but honestly, they want to sell your house and they are used to giving people unrealistic numbers for what they think is the maximum sales price. So in your situation they may or may not give you the best number. An appraiser is used to telling banks whether a home is actually worth as much as people are trying to pay for it. And get your own appraiser - if H doesn't like the figure he can go out and get his own independent appraisal.
And you can get a rough idea in the meantime by seeing what comparable homes have sold for in your area. Although as pointed out, this is a lagging indicator and if home prices are falling now, may not reflect that drop yet.
