Home builders hold few fond memories from the summer of 2010, with its post tax credit home sales crash. But with the dog days behind, and the first day of fall near, some hold hope that the market will heat up as the thermometer falls.

There is some anecdotal evidence that sales were improving by the end of summer. Publicly held builders reported in August that July was better than June and that August, usually a slow month, was looking better than July.

During her monthly survey of home builders, Jody Kahn, a vice president for John Burns Real Estate Consulting, said many builders reported stronger sales and higher traffic toward the end of August.

"Some of the builders have been commenting on better-than-expected Labor Day" weekend traffic, Kahn said.

Of course better is a relative term as sales still remain at record lows for many builders. But they do have one new powerful tool that some have already started to wield in their fall sales campaigns -- record-low interest rates.

That, paired with low home prices, could help builders gain some sales as 2010 rolls to a close, Ara Hovnanian, CEO of Hovnanian Enterprises, said on CNBC Thursday morning.

And the company's web site is promoting that one-two pitch.

"This is your once-in-a-lifetime opportunity to get the lowest interest rates possible on your mortgage," screamed a "Breaking News" headline on Hovnanian's website.

Lennar, too, flashed interest rates of 3.375% and 4.33% for fixed on it's website during its "Summer's End" sales promotion.

M/I Homes translated the low interest rates into "Historically Low Payments" on its website, pushing its "Smart Move" promotion. Roll the cursor over the city or market you are interested in and a monthly payment figure pops up on the screen.

Even higher-end builders are pitching the low interest rate equals low payment message. Standard Pacific Homes has a "low monthly payment" tag on its home page. And Toll Brothers has "historic low interest rates" on its lists of sales motivators.

The pay back for green, energy efficient construction was another common message on builder sites.

Meritage Homes advertises that its houses save 45% on energy costs. Ryland Homes also touts its homes' energy efficiency.

Avatar Homes has created a highly unusual promotion to generate leads. It is offering to donate $1,000 to the favorite charity of anybody who refers someone who ends up buying a home from the company.

"Help us Pave the Way to a Better Nation" a box on its web site promoting its Solivita active adult subdivision outside of Orlando.

The successful lead providers will also get something, literally, more concrete as well -- their name engraved into pavers in the development's "Circle of Palms."