Why homes often feel hotter than the thermostat suggests – what to do about it

Two houses on the same street: one built in the 1950s and the other in the 1990s. There are no trees or other shade. The air conditioning units are the same, recently replaced, and working perfectly. The same thermostat is set at 82 degrees Fahrenheit (27.8 Celsius). When the outside temperature is 110 F (43.3 C), a 1950s house will likely feel at least 10 F (5.6 C) warmer inside, even with the same air temperature. Why? The answer is related to the scorching heat. Warmth is what keeps you warm around a campfire on a cold winter night. Fire does not overheat the air; Rather, like the Sun, most of the fire’s heat travels through invisible waves directly from the campfire to your body. In the sweltering heat of the Arizona sun, the surface temperature of my home, which is one of 41,000 homes built in Tucson during the post-World War II era without insulated post-and-beam ceilings, is 100 F (37.8 C). can reach more than

Single-glazed steel windows register 122 F (50 C), and uninsulated concrete block walls don’t get much colder. Inside my house on triple-digit days, it can feel like I’m standing near a campfire, even with the air conditioner maintaining 75 F (23.9 C). And when the system doesn’t work — as happened during the long-running 2023 heat wave, when the mercury reached 110 F (43.3 C) every day for weeks — temperatures rise dangerously quickly. . Without AC, the warm surfaces and the gusts of wind from the ceiling fans make the house feel like an air fryer. Air Temperature: An Incomplete Indicator of Comfort While people are used to thinking of how clothing, wind movement, temperature and humidity affect comfort, two lesser-known measures help explain how comfortable they feel indoors. How to do it: Average temperature This is the average temperature of all the surfaces around us: ceilings, windows, walls, floors.

In order for radiant heat to be transferred between an object and the human body, it needs an unobstructed access between the two, so the ceiling and unobstructed windows make a big impact on the radiant temperature experienced in a specific location in the home. . Operating temperature It can be estimated from the average temperature in a room and the average air temperature. Other calculations of operating temperature take into account the effects of wind speed, humidity, and additional factors. About half of how you feel comfortable is determined by the environment. Unfortunately, as building scientist Robert Bean says, an entire industry of manufacturers, suppliers, builders and traders wrongly associates thermal comfort with air temperature. The result is that most people are completely oblivious to what actually makes a space feel comfortable or uncomfortably hot.

On a hot, sunny day, good insulation and double-pane windows transfer less heat to the air conditioning, keeping the average temperature inside the building within a few degrees of the outside air temperature. However, in an under-insulated building, such as my house, or some older public housing projects in Phoenix, high average temperatures can push operative temperatures over 90 F (32.2 C) – even with the thermostat set to 75 Even when set to F (23.9 C). When the surface temperature exceeds our skin temperature, the heat from the hot surface will begin to dissipate into the body, making heat stroke more likely. Although there is debate over the exact threshold where overheating becomes dangerous, most people would agree that 90 F (32.2 C) is well beyond the limit of comfort. Small buildings, such as mobile homes, tiny houses, shipping containers and garages turned into apartments, often feel uncomfortable regardless of the thermostat setting because of the heated surfaces.

Smaller structures expose the occupants to three, four or even six surfaces and their exterior is exposed to the sun and warm outside air. The hotter the surface, the more discomfort. Cooler Surfaces, More Comfort If you live in a less insulated building and you don’t mind using more electricity, you can set the thermostat down. But if the average temperature is higher, a 2 F (1.1 C) drop in air temperature will only feel like 1 F (0.6 C) — and those hot surfaces will still make you feel uncomfortable. Adding insulation to your roof and replacing single-pane windows with double-pane units with low-emission (Low-E) glass can help lower average temperatures and your energy bills. Those are expensive fixes, but new federal tax credits and upcoming exemptions from individual states can help you out.

Trees, canopies and outdoor shade can also reduce the average peak temperature by blocking direct sunlight. However, glass is a poor insulator, so in very hot climates, single-pane windows that are completely protected from the sun can still get uncomfortably hot. Adding a curtain inside and keeping it closed can help reduce the average intense temperature as the curtain will be closer to the temperature of the air than the glass. What about tenants in older buildings? Tenants in older, less insulated buildings are often less able to afford large energy bills, and landlords may be unable or unwilling to make costly improvements. Making matters worse, older air conditioning systems use two to three times more energy than newer units to provide the same amount of cooling. Because the thermostat needs to be set lower to create a comfortable operating temperature, an HVAC system in an under-insulated building must work harder and longer, using more energy and further increasing costs.

And the cost of discomfort is not only financial: hot buildings also have adverse effects on health and productivity. Millions of Americans now live in places where cooling is the only thing keeping massive numbers of people from the heat. In Phoenix, city code requires rental units to be cooled by air conditioning so that the temperature does not exceed 82 F (27.8 C) as measured 3 feet above the floor in the center of the room. Unfortunately, the code doesn’t specify whether 82F is the operative temperature or the air temperature. That one word makes a huge difference. In an older, less insulated building similar to my house – or, worst case scenario, the top floor of an uninsulated concrete high-rise building, the air temperature in the sun-baked southwest unit appears to be a safe 82 F. but dangerous operating temperatures of 96 F (35.6 C) or higher can easily be hidden behind it. The Key to Better Design Comfort As a professor of architecture and building science, I believe that today’s Byzantine building codes and rental regulations greatly improved comfort by regulating average radiant temperature instead of air temperature May go.

Interior surfaces, which are easy to measure with an inexpensive infrared thermometer, should be kept within a comfortable range above 60 F (15.6 C) and below 85 F (29.4 C). For more comfortable buildings, architects and engineers can apply simple, established principles such as natural ventilation, shade and the right insulation and windows for the climate. Firstly keeping the heat away means we don’t have to spend as much on energy for cooling. Research shows that these measures can also make us safer by keeping buildings cooler for longer during summer power cuts. The happy result: homes and other buildings that are not only comfortable, but also safer and more economical to operate.

Disclaimer:IndiaTheNews has not edited this news. This news has been published from PTI-language feed.

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