Can’t Afford A/C? Try These Natural Alternatives

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Written by Leigh Matthews, BA Hons, H.Dip. NT


Leigh Matthews, BA Hons, H.Dip. NT

Sustainability Expert

Leigh Matthews is a sustainability expert and long time vegan. Her work on solar policy has been published in Canada's National Observer.


Let’s face it, air conditioning is expensive, both in buying the unit and in keeping it running. Some of you in more northern climates (hello Duluth and the northern Great Lakes) or near the coast (we see you La Jolla) may be able to get away with natural ways to cool your home in the summer rather than resorting to A/C. If you’re looking to bypass the A/C unit and go back to basics, this post is for you.

Table of Contents
  1. Do we really need air conditioners?
  2. Air conditioning alternatives 
  3. Innovative air conditioners

Do we really need air conditioners?

In a word, yes. Whether we want to face it or not, the global average temperature is rising (and, scarily, twice as fast in Canada, where I live!). This means that areas that previously had a temperate climate are fast becoming unlivable without adequate air conditioning in summer.

High summer temperatures are a significant cause of death worldwide, with older adults, infants, children, and those with chronic health conditions especially vulnerable.

According to the U.S. Centers for Disease Control (CDC), almost all heat-related deaths (94 percent) occur from May to September. Between 1999 and 2010, more than 8,000 people died as a result of heat exposure, with the highest numbers reported during July (3,145; 39%) and August (2,138; 26%).

Which states are most at risk of heat-related deaths?

Three states accounted for almost half (43 percent) of all heat-related deaths by themselves: Arizona, Texas, and California. However, those who live in the midwestern and northeastern U.S. are more vulnerable to the effects of heatwaves, simply because residents in these areas are not accustomed to high temperatures and many buildings are not equipped with air conditioners.

As an example, in Austin, Texas, daily average temperatures don’t fall below 90 degrees between June and September, with many days now topping 100 degrees Fahrenheit. Hyperthermia (heat stroke) can set in within just 30 minutes at temperatures over 104 degrees. Now, consider that these daily averages are outside temperatures. The temperature inside a high-rise sandwiched between other high-rises is typically even higher.

Unsurprisingly, then, the majority (81 percent) of heat-related deaths occur in urban areas, thanks, in large part, to the heat-island effects in cities. As we pour more concrete, pave over the natural ground, cut down trees, decimate grasslands, and generally have less and less green space, the earth itself heats up by soaking in the heat of the sun. And, as we install more A/C units, the hot air is pumped back out into the city.

What’s more, the coolants or refrigerants used in most air conditioners also contribute to global warming. Sure, we pressed governments worldwide to ban the use of CFCs (chlorofluorocarbons) because they were depleting the ozone layer, but their replacements are hundreds or thousands of times worse for their global warming potential. The good news is that these replacements, such as R410-a and R32, are more efficient than CFCs, meaning that A/C units use less energy now than they did in years gone by.

However, in the U.S., a staggering 13 percent of the average household utility bill is spent on cooling, according to Energy Star. Then, in the winter months, we spend our money heating the air in our homes. Many eco-minded and frugal folks have realized that this seems like a lose-lose situation and are figuring out better ways to manage indoor temperatures year-round. Which brings us to…

Air conditioning alternatives 

Pushing a button on an A/C unit is a wonderful thing and absolutely necessary for comfort and safety in some locales. If you’re concerned about your pocketbook, the noise, and the use of energy, you may want to try minimizing your need for A/C with some alternative ways to cool indoor air.

Heat sinks and pumps

Some folks, for instance, install heat sinks and pumps to capture hot air in summer, store it in tanks underground, and pump it back into the home during the colder winter months. For most apartment buildings, having a storage tank underground isn’t feasible, but single dwellings can be designed with such a system and are worth looking into.

Alternatively, some people are installing split air conditioner heat pumps in place of a straight-up A/C unit and indoor heater. These units sit in a window or on a balcony and capture heat from outdoor air to pump into the home in winter, then reverse this action in summer to help keep air cooler inside. Such systems may be eligible for government rebates in some areas and can be much more cost-effective compared to buying two separate appliances.

Swamp coolers AKA evaporative air conditioners

Evaporative coolers or ‘swamp coolers’ are a decent option for air conditioning in hot, dry climates. These units cool outdoor air through evaporation and then blow it inside to cool indoor air. They use around a quarter of the energy of a traditional air conditioner, are quicker and easier to install, and are mobile.

Swamp coolers are a bit of a pain, however, in terms of upkeep. They are hard to maintain if you don’t have some technical know-how and time. They’re also not as effective as some A/Cs, so you may have to supplement with other alternative air conditioning methods or acclimate quickly.

Ice, ice, baby

Anyone without an A/C who has experienced a sweltering hot night probably knows the fan-plus-bucket-of-ice trick for creating a targeted stream of cool air. Happily, this old-school technology has been conveniently packaged by California-based Ice Energy who makes and sells the Ice Bear system.

This system is designed for apartment/condo and commercial/industrial buildings to augment existing roof-top air conditioning systems. It consists of a large thermal storage tank that makes ice at night and releases cold air during the day as needed. Because energy is cheaper at night, this helps keep cooling costs low. The technology hasn’t yet been scaled to make it work for smaller spaces, however.

Natural air conditioning using thermal mass

If you live in an area where outdoor air temperature fluctuates significantly from morning to night, you can set up your own natural air conditioning system at home. This may take some careful calculation and organization but could save you a lot of money and make for a much more comfortable living situation. Basically, you’ll need to work out when to suck in and store cool air and when to keep your home sealed off to prevent hot air sneaking in.

To do this without an actual heat sink, you’ll need to know about thermal mass and Btus, and use this newfound knowledge to your advantage. Thermal mass dictates how much coolness or heat you can store in your house. It is why large empty tents heat up quickly but small basements full of junk stay cold even on the hottest days.

Understanding Btu

Let’s get to know Btu. Put simply, a Btu is the amount of heat needed to warm one pound of water by one degree Fahrenheit. To heat a 16 oz glass of water (which is a pound of liquid) from a room temperature of around 60 degrees Fahrenheit to boiling point (212 degrees Fahrenheit) would take 152 Btu, for example.

Now, consider you’re trying to heat a room that measures 10 ft x 10 ft and has a 9 ft ceiling. Assuming the room is empty aside from air, there’s 900 cubic feet of air in the room, which weighs approximately 73 pounds.

Air has a specific heat capacity of 0.24, and the density of air is 0.075 lbs per cubic foot. Therefore, to heat the air in that room from 60 degrees to 80 degrees requires an energy input of 0.018 Btu per cubic foot (0.24 x 0.075), amounting to 324 Btu (900 x 0.018 x 20 degrees).

To heat the air in this room by 20 degrees appears, then, to take just over twice as much energy as it does to boil a 16 oz cup of water. In the case of your actual living room measuring 10 ft x 10 ft with 9 ft ceilings, this isn’t the case. Why? Because of thermal mass.

In the average living room, there’s likely to be more than a thousand pounds of drywall, several hundred pounds of hardwood flooring, and a couch, coffee table, and other furniture weighing in at a few hundred pounds. As a conservative estimate, let’s say the total mass in this room is around 1500 pounds, plus the 73 pounds of air itself.

It should be clear by now that it will take far more energy to heat up all that mass than it would to simply heat 73 pounds of air. Especially considering that the density of almost everything in this room is higher than the density of air. Even assuming your mahogany coffee table has the same density of air, in our scenario we would need 1573 x 0.18 x 20 to heat up the room from 60 degrees to 80 degrees, amounting to 5662.8 Btu. Quite a bit more, then, than boiling a couple of cups of water.

Why does this matter when thinking about air conditioning? Well, because folks with a minimalist aesthetic will find it takes less energy to heat up a room than those with a maximalist aesthetic. In practical terms, if you have a sparsely furnished apartment with little thermal mass in the way of hardwood or stone flooring, tiles, and dense furniture, it will get hotter faster and cool down quicker. In summer, this means you’ll have to run the A/C harder and in winter you’ll have higher heating bills.

(As someone with a ‘bountiful enthusiasms’ aesthetic, I’m keeping this one in the bank as an excuse for later use. Math to the rescue, once again!)

Put another way, traditional homes in hot climates are often made with thick stone or adobe walls. These walls contain a lot of thermal mass and it takes almost all day for heat from outside to penetrate to the interior side of the wall. Say the temperature gets up to 80 or 90 degrees Fahrenheit during the day and drops to around 65 at night, this kind of wall construction makes a lot of sense. That’s because the house will stay cool during the day and the walls will release heat inside and outside overnight, helping to keep occupants warm even as it turns cooler outside. This cycle repeats daily and is ideal when there is a 10 degree temperature differential between daily high and low where you live. To fully nerd-out on thermal mass, start here.

How home materials and decor play into the choice of air conditioning

Now, let’s think about how this translates to your choice of A/C. If, as described, your home contains a lot of thermal mass from heavier construction and furnishings, you can likely get away with an A/C unit that has a lower BTU rating. If, however, your home is less solidly built and contains little furniture, you’ll be at the higher end of that aforementioned sq. ft. to dollar ratio.

If you own your home, your best bet is to switch out old carpeting for stone floors or hardwood floors and eco-friendly rugs, add some insulation, and create your own heat sink. Think heavy when refurbishing and renovating. This will help you stay comfortable year-round and cut your energy use and costs. You may even be able to handle the summer heat with a few strategically placed fans by open windows at night, helping suck in cooler air while closed windows and heavy, reflective drapes help keep heat out during the day.

You might also look at eco-friendly products specifically designed to act as a heat sink, such as the ZEF dining table. This table acts as a thermal sponge, similar to the ridged heatsinks on top of a processor inside a computer. The table has a solid oak top beneath which is a folded sheet of anodized aluminum with tiny wax balls filling the gaps in-between the folds. These balls constitute a ‘phase change’ materials, meaning that they absorb heat from the air, helping to cool a room during the day, then release the air as the temperature cools at night.

Innovative air conditioners

One innovation in air conditioning that I’m particularly excited about is a water-based, chemical-free air conditioning system designed by researchers at the University of Singapore. Instead of using vapor compression like almost every other air conditioner out there, this system uses membranes to remove moisture from humid outdoor air, cools the dehumidified air using water as a coolant, and then discharges the cool air indoors. As a bonus, the system also produces up to 12-15 liters of potable drinking water per day.

The scientists behind this new type of system claim that it consumes about 40% less electricity than current compressor air conditioners, making it much more eco-friendly, especially when you factor in not relying on hydrofluorocarbon coolants.

To really get into the weeds on this one, check out this patent for a membrane microgravity air conditioner.

If you don’t fancy building your own A/C and the other alternatives aren’t available to you, traditional air conditioners can help you stay cool this summer. Pick a good one and you could save a lot of money, avoid nuisance noise, and even keep indoor air contaminants at bay.

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