By Jim Cavan and Ed Henningsen

It’s no secret that many people – and countless thousands here in New England – love their old homes, particularly those dating to the 18th or 19th centuries. Whether it’s their architectural uniqueness, links to our forefathers, the remembrance of certain smells, or the comfort one feels when standing beneath their often majestic structures, there’s just something that attracts us to them.

Whatever the appeal, pretty much anyone who fits this description will at some point be met with the challenge of preserving their beloved home for the next 100 years. Specifically, homeowners must figure out how to most efficiently heat them. In doing so, they’re often confronted with a subsidiary challenge: that of an unfinished, drafty basement or crawlspace.

First, some facts. Whether we like it or not, three aspects of Mother Nature will ultimately deteriorate just about everything on the planet: Water, heat, and ultraviolet light. Here in New England, water or moisture is generally thought of as the chief concern amongst the three; mold and wood rot can often overtake a basement, if spores and moisture are left unchecked and there are enough organic materials for them to feed on.

Obviously, removing the organic materials – original wood beams, manufactured lumber, paper products, etc. – is at the very least a hugely difficult proposition, and at most impossible. With more modern materials such as sheetrock backing paper, manufactured lumber, or OSB board, the heat-intensive manufacturing process often results in bringing out carbohydrates latent in the wood – the sugars on which mold loves to feast. That leaves removing moisture as the only feasible way to prevent rot and decay.

Another factor inhibiting the performance of basements and crawlspaces is heat loss. In some homes, it’s that big old beasty boiler or heat-spewing furnace. It might be that aging water heater rusting in the corner. Or it might be the omnipresent tangle of piping, pumps and wiring weaving about the basement ceiling. Most Boilers and water heaters – along with their associated piping – will lose heat over time. These are called “standby loses,” and they can be significant.

Physics dictates that heat goes to cold all the time, and never the other way around. Foundation walls – be they rock, brick or concrete – typically have an R-value (the number used to determine efficiency or “tightness”) of less than 1. To put that in perspective, a single pane of glass has an R-value of around 1. Therefore, if it’s 10 degrees outside, the exposed portion of your foundation wall won’t be much warmer; maybe around 15 degrees or so. That means a significant amount of heat is continually flowing through the walls into the outside air or into the frozen ground. Sure, some of it will rise into the house; but a vast majority of it will be lost. And that’s not going to do anyone any good, is it?

Many turn-of-the-century homes feature rubble or stone foundation walls and dirt floors, with the proverbial “trout stream” being a common occurrence every spring. If a basement has moisture on that level, that means you have a moisture or heat lose issue on your hands. While most of the old homes encountered by energy auditors have a heating plant that is typically 45 years old or older, the hot water heater may be just as old. Understanding this, what steps should you take to improve your basement?

There are several approaches, depending on the house and the severity of the heat loss or moisture issues at hand. An energy audit, conducted by a certified specialist, will help identify which steps will work best for your home. With respect to water issues, gutters, downspouts, French drains and landscaping can often be targeted in an effort to keep surface water out of the basement. Dehumidifiers can be a good option, so long as they can run when needed. In more extreme conditions a moisture barrier might be recommended, often in the form of a rubber or heavy cross hatched polyvinyl membrane that extends from the rim joist down the foundation walls and across the floor, with all seams overlapped and sealed. What happens on the other side of the membrane doesn’t matter, because water can no longer get into the home.

Heat loss through the walls, meanwhile, can typically be handled with solid insulation. Because heat in the basement has nowhere to go but up, insulating the rim joins and foundation of the walls to below the frost line will prevent a significant amount of heat loss. There are several ways to achieve this, depending on one’s budget. The most expensive – and most effective – option is spray foam insulation, which requires a fire-retardant “overcoat.” As a more economical option, rigid insulation or fiberglass batts – if installed with a moisture barrier – can also be used. Additionally, basement windows can benefit from additional panes of glass which help further bolster their overall R-value.

Lastly, changing out old heating appliances will almost always save you money in the long run. New units – whether for heating or hot water – are better insulated and operate at higher efficiencies. Not sure how your unit stacks up? Have an energy auditor test your unit’s efficiency beforehand to make sure the savings are really there to be had. If you decide to invest in a new furnace or hot water system, an auditor can help you understand a contractor’s often confusing sales pitch and quotes.

In short, having an energy auditor inspect your home – and in particular that old drafty basement, attic, or crawlspace – should be the first step in helping identify your old home’s efficiency shortcomings, as well as the possible fixes. As an independent sounding board, an auditor can help you though the often trying process of bringing that 19th or 18th century home up to 21st century par. While energy auditor fees are typically in the $500 range, any auditor worth their salt should easily save you the cost of the audit, in the process helping assure that your unique home is ready to perform – and perform efficiently – for another century.