Ask Hannah Holmes

Hannah Holmes

Home Rx

Realtor/science writer/self-proclaimed “house geek” Hannah Holmes on evaluating heat pumps, cavemen’s home-furnishing habits, and more.

Illustrations by Christine Mitchell Adams

Have a question for Hannah?

Send your Maine home or garden conundrum to [email protected] and we may feature it in an upcoming column.

What are the most effective ways to resolve humidity issues in a cottage crawl space?

seasonal crawl space

It is easy to forget that the primary job of a seasonal crawl space is not to hide the kayak from hooligans or stash lawn chairs whose ratty nylon webbing you will definitely repair soon.

The crawl space’s primary job is airflow. The earth is wet. The floor of your camp is dry, ideally. The buffer between them is air. If air is allowed to flow in, absorb some moisture, and flow out, all is well. But if moist air can’t depart, it sullenly distributes humidity to everything it touches. Molds thrive in humidity, and thriving mold smells bad and damages buildings.

So look for barriers to free-flowing air: Is there a berm of rotting leaves? A funky fortification of plywood? Is the crawl space filled to the gills with firewood and rusted barbecues? Clear away the obstacles and rake out the leaves. If the air is still too still, you may also need to prune back shrubbery growing nearby.

Are heat pumps worth the hype? How expensive are they to run?

heat pump

Hype? Hype, you say? Heat pumps are magical, physics-defying boxes of wonderful!

Ok, ok: They don’t actually defy physics. Rather, they exploit the second law of thermodynamics. By compressing and expanding gas, they extract tiny amounts of heat from the outdoor air, and then distribute that heat to “heads” inside your house. If you think of old space heaters as 100 percent efficient — all incoming electricity is converted to heat — then think of heat pumps as 200 to 400 percent efficient.

If that sounds like sorcery, you may prefer to follow the money: Locate the “Compare Home Heating Costs” tool at Enter your current fuel usage and price, and it will calculate your bill if you used different fuels. Heat pumps usually win.

A word of warning: Heat pump efficiency plummets if you demand a sudden heat increase. Hidden inside many models is a backup space heater that can boost output quickly. On my units, if I crank up the heat more than a couple degrees at a time, a warning light blinks. It’s green, like money.

Also: Shortly after installation, my outdoor condenser malfunctioned. The replacement part took three cold days to arrive. I was very glad to have a gas fireplace. Some models offer an “emergency” mode that relies entirely on the space heater if the condenser dies.

And: If heat pumps are replacing a decrepit furnace in your drafty basement, you may discover, as I did, that the furnace’s “waste heat” was keeping your plumbing thawed. I should have had a whole-house energy audit done prior to galloping into the 21st century. Revisit Efficiency Maine to find auditors, rebates, and other expertise.

What is a good plan of action for purchasing a Maine camp, cabin, or cottage when I live out of state?

Maine real estate

Let’s just call it a camp, shall we? Unless your goal is a quaint shingled dwelling by the ocean (that would be a cottage), or the weekly rental of a motel unit (that would be a cabin), then you’re probably looking for a camp: a seasonal hangout of any stripe, usually near water.

The more research you do from the comfort of your four-season home, the more fruitful your visit will be when you buddy up with a broker.

What kind of community suits you? Large lakes lend themselves to motorized sports and far-ranging exploration. Smaller ones offer quieter pursuits and modest horizons. Likewise, seaside options range from busy villages to silence and spruce trees. As for water access, will you be swimming? Canoeing? Tying up the boat you sail home from the Caribbean? Do you need robust internet access? Reliable cell service? A nearby hospital or veterinarian?

The answers will help narrow your search. Here are some of my favorite armchair research sites. Database with tons of facts on each lake or pond: Cell service maps: or Scuttlebutt: A town’s website and Facebook page may hint at the place’s personality. You may even find minutes from the planning board and selectmen’s meetings.

To locate lurking gravel pits or loud highways — or a neighbor with a really nice boat: Google Maps, satellite view.

When choosing countertops, should you consider the fact that granite off-gasses radon? How long does it give off radon?

does granite off-gas radon?

It can be gratifying to reflect on how far we’ve come as a species. Whereas we began the human era sheltering in stone caves, sitting on chunks of trees, and wrapping our feet in animal hides, today we find ourselves sheltering in stone (brick, granite, gypsum) houses, sitting on carved-up trees, and wrapping our feet in animal hides.

While most rocks contain uranium, granite contains more than most. That uranium eventually decays into radioactive radon, which migrates upward through rock and soil. Most of our exposure to radon results when the gas seeps into a basement then gets trapped in the house. In Maine, our annual rock radiation exposure equates to about two-thirds of a CT scan. (Iowans get twice as much.) Radon can cause lung cancer.

But how much radon does a countertop add to your lifetime exposure? DIY testing with an instrument known as a Geiger counter or strategically placed radon samplers isn’t reliable. (Bananas are naturally radioactive and will also set off a Geiger counter.) The few countertop studies I located concluded with words like “negligible,” “unlikely,” and “less than average outdoor concentrations.”

Hannah Holmes is a real estate broker at Keller Williams Realty Greater Portland and the author of four science titles, including The Secret Life of Dust and Suburban Safari. A veteran renovator of old houses, she blogs about humans and their territorial issues at