Summer Weatherization Tips: Part Five

On the hottest days in summer, a house cooled to the low 80’s may just not be cool enough, especially with high humidity conditions and if you have underlying health concerns. If central air conditioning is a need, and you are stressing about the cost and logistics of installation within your historic home, fear not – modern central air systems do not require large duct work as it did in previous decades, and can even be installed without any duct work at all! As a bonus, these systems can also shift seasonally to assist or replace your existing heating systems.

A through-the-wall ductless HVAC system costs about $500 (plus installation) for up to 12,000 BTUs of cooling on a 110V service. These systems work especially well with traditional closed floor plans – each air handler can be controlled independently, so you can target the cooling to the spaces you are using, saving on energy costs.

A high-velocity HVAC system uses mini-ducts, which are usually about 3” in diameter, and often are snaked between floor joists or through walls. These use small vents, which you can match to the aesthetics of your home interior design.

The first step to deciding a system is to determine how much cooling your home will require. First determine the floor square footage- multiply the length by the width; if the space to be cooled is not a square or a rectangle, adjust with the appropriate square footage equations for the shape. Multiply this amount by 25 to determine how many BTUs of cooling will be required or refer to this table from (click for larger version)

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A one-ton central AC system can remove 12,000 BTUs in an hour – after you have the number of BTUs needed for your home, divide this amount by 12,000 to determine the tonnage needed for the HVAC unit. A 1000 square foot house will require a 25,000 BTUs of cooling, or a 2.5-ton system.

(SQ FT X 25) = AC unit tonnage required

Be sure to also check the unit’s efficiency rating, or Seasonal Energy Efficiency Ration (SEER) to see how long it will take before the investment in this system pays off. This will likely be on the yellow EnergyGuide sticker on the unit.


Summer Weatherization Tips: Part One

Summer is here at last!

Due to social distancing, most folks are now spending much more time at home this summer, and plan to continue to utilize remote work plans for the indeterminate future.

While we have by now adjusted to wearing sweat pants during meetings with the boss and to transforming our kitchen counters into office desks, summer heat adds a whole new element we need to adjust to – if you relied on AC at the office during the daytime, you likely already feel the heat and humidity creeping up, and are dreading the late August temperatures of parts of your home.

In this series, we will go over some basic tips for how to cool your historic home, touching on architectural elements that you may not think of that are designed to help keep things chill- if your home was built before 1950, it likely already has many of these elements built in, just waiting for you to rediscover them!

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Summer Weatherization Tips: Part Four

Few people genuinely enjoy hot humid days – but in addition to the physical discomfort, these environmental conditions are also dangerous for our health.

Poor air quality is one of the increased hazards – smog events occur when heat and sunlight “bake” chemical pollution in the air, increasing ozone levels. But did you know that, according to EPA research, indoor air quality can actually be 2 to 5 times higher compared to outdoor air quality, even on higher risk days?

What can we do to reduce the risks in our homes? First step is identifying potential sources for poor air quality indoors. The EPA identifies these as the most common sources in most homes –

  • Fuel-burning combustion appliances
  • Tobacco products
  • Building materials and furnishings as diverse as:
    • Deteriorated asbestos-containing insulation
    • Newly installed flooring, upholstery or carpet
    • Cabinetry or furniture made of certain pressed wood products
  • Products for household cleaning and maintenance, personal care, or hobbies
  • Central heating and cooling systems and humidification devices
  • Excess moisture
  • Outdoor sources such as:
    • Radon
    • Pesticides
    • Outdoor air pollution

Finding and removing (or at least venting) these sources where possible will improve indoor air quality. In fact, the simple act of cleaning our living spaces regularly will improve air quality (and, setting aside the seasonal risk, we should all be taking steps to clean regularly anyway to reduce risks from COVID-19.)

Consider investing in a vacuum cleaner that has a HEPA filter, especially in spaces with carpeting, and remember to wash overlooked household items, like bedding or curtains.

Ultimately, remember that our historic homes are designed to “breathe” – pop open a window whenever possible for better ventilation. Use fans to circulate fresh air through the house. During high humidity events, use a dehumidifier in enclosed spaces to reduce the risk of mold and mildew.

Learn more at these links:

Summer Weatherization Tips: Part Three

Fans can be surprisingly efficient in cooling homes if used properly, and cost much less than an air conditioning system to run. Running fans in historic homes built before 1950 also requires much less retrofitting- generally just some maintenance to better insulate and vent, especially in attic spaces.

Did you know you need to change the direction of the airflow from fans depending on the time of day or year?

If you have ever been in an argument about which direction a box fan in a window should face, you may be surprised to learn that box fans should be flipped around depending on the time of day. During the daytime, face box fans in windows outward to force trapped hot air inside the house out, especially on the upper floors of the home. After dark, flip the fans back around so that the cool nighttime air is pulled inside to cool. If you have windows that open at the top, popping these open at night will also help with this circulation.

Ceiling fans should be set to spin counterclockwise in summer, which will force cool air downward. In winter, these same fans should still be set to run, but should be set in a clockwise rotation; this will help circulate the heating evenly throughout the room.

You can also install a whole-house fan; this will require a bit of retrofitting of the attic space, but will pull and circulate the air flow of the entire house, improving indoor air quality and helping to very efficiently cool everything off.

To learn more, visit these links: