How Long Does It Take to Cool a House with AC?

Your AC’s cooling power depends on several factors, such as its size, power, and the size of your home. The outside temperature too affects the time your house has to cool. How long does it take to cool a house with AC?

It takes about 3 hours for a properly functioning AC unit to cool a 4-bedroom house. This length of time is applicable only when your attic and basements are well insulated. If they are not, it will take more than 3 hours to cool your home.

Aside from the aircon’s efficiency, other factors could contribute to the amount of time it takes for your house to cool. 

Read on to learn more about cooling your house faster, the factors that affect the cooling process, and important energy-saving tips.

How Long Does It Take to Cool a House with AC?

how long does it take to cool a house the first time the air conditioner is started

Cooling a 4-bedroom house would take at least 3 hours. You must have a properly functioning AC and a well-insulated home. This length of time applies only when there are no air leaks in your house. It will also take a longer time to cool your house when the climate is warm.

The longer it takes for your place to gets cold, the more expensive your electric bills will be. However, there are ways to cool your house faster. See 9 different ways below.

1. Consult a Professional

You have to let a professional assess your house and determine how much AC tonnage you need to cool your home.

Consulting a professional will prevent you from wasting electricity as an unsuitable aircon will not cool a house no matter how long you turn it on.

A certified technician must, likewise, check your refrigerant levels and recommend ways to maximize your AC. The AC cannot effectively eliminate the heat from your house with low refrigerant levels.

2. Ensure Your Air Filters Are Clean

Dirty filters will prevent air circulation and efficient cooling of your house. You have to change dirty air AC filters so that air can flow smoothly around the room.

3. Check for Leaks in Your House

Your basement or attic may have unsealed rim joists or air ducts that can leak air. Air leakages will lengthen the time for your house to cool. This occurs because they can spread as much as 20% to 30% of conditioned air.

Inspect your house thoroughly and then seal all leaks to increase your ACs cooling capacity.

4. Put a Basin of Ice in Front of the AC

This method will allow the air that comes out of the aircon cooler. Thus, the cooler air will facilitate the lowering of your house’s temperature more rapidly.

5. Keep Your Windows and Blinds Closed

Keeping your blinds or curtains closed will minimize heat from entering your room; thereby, it hastens to cool. Inspect your windows too and close all of them. Make sure that there no leaks exist in your windows.

6. Keep Your AC on When Going Out for Short Periods

Keep your AC on if you go out for short periods. It is more energy-consuming to turn off the aircon and then turn it on again when you come back. This is because the AC has to cool the warm air again instead of just maintaining the cool temperature.

However, if you plan to stay away from home for a long time, you should turn off your AC to save energy. This step will also allow your AC to rest. 

7. Turn on a Fan

Most users recommend turning on your fan to increase cool air circulation. The advantage of air circulation against the heat generated by the fan is more. You can turn on at least one fan to increase cool air circulation. 

8. Set the Default Temperature Correctly

It would be best to set the default temperature at 24 °C (75.2 °F) instead of 18 °C (64.4 °F.) Setting a cooler temperature does not automatically shorten the cooling time. You could risk the system freezing up with low temperatures.

You may lower the default temperature during summer and when there are no infants or elderly family members.

9. Grill Outside Your House

Grill outside your house to prevent adding heat to your house’s interior. You could even opt to cook outside if you can. Cooking inside will increase your home’s temperature and will add more heat for the AC to cool.

How Long Should It Take to Cool a House from 80 to 72F (27 to 22C)?

It takes a longer time to cool a house during hot weather. For your home to cool from 80 to 72 degrees Fahrenheit, you need between 4 to 6 hours. The efficiency of your centralized air-conditioner contributes significantly to your house’s cooling speed. 

how long does it take to cool a house

Cold weather decreases the amount of time your AC will cool your house. Hence, you should maintain your thermostat at a reasonable level.

You can refer to the factors mentioned below to speed up your house’s cooling process.

How Long Does It Take for a House to Cool Down with AC?

How long should it take to cool a house 10 degrees? An AC that’s in good condition will be able to cool a four-bedroom home by 10 degrees after three hours. Several factors affect this length of time.

And these factors are:

1. AC’s Working Condition

Old air-conditioners tend to cool slower than brand new units. The old units usually undergo wear and tear that could slow down the process. 

2. AC’s Size 

The smaller the AC is, the slower it gets to cool a house. That is why it is crucial to use the appropriate size relative to the size of the house. Using a big AC for a small place would also be a waste of energy. 

You wouldn’t want your electric bills to bore a hole in your pocket, for sure. The unit must have a suitable tonnage for your house.

There are various factors to consider when calculating the ideal size of your air conditioner. These are the number of windows, the ceiling height, type and color of the roof, and heat transfer of walls. [1]

You may need a cooling expert to determine the exact AC type that you need. You could also use a calculator to find out the correct AC tonnage.

3. Size of House

Bigger houses take longer to cool than smaller homes due to additional footage to cover. You can use a larger AC to hasten the cooling process up to a certain extent. But this method would be expensive and impractical.

Using a suitable AC for your house will guarantee that you get the coolness you want at no additional cost.

4. Outside Temperature

Warm climates lengthen the time that your house will cool due to increased heat and humidity. On the other hand, cool temperatures will hasten the cooling of your home. This occurrence happens due to the lesser heat that the AC has to cool.

5. House Structure

Your house structure affects your home’s cooling time. If your house is more exposed to direct sunlight, it will take a longer time to cool. Shaded homes usually take a shorter time for the AC to cool them.

Houses subjected to sunlight from 10 a.m. to 4 p.m. tend to cool longer. Early morning sun does not affect the AC’s cooling capacity significantly. Early morning sunlight is also good for your health. 

6. Internal Heat Sources 

The presence of heat sources inside your home, such as light fixtures, heat-generating appliances, and electronics, increases the amount of your AC’s cooling time.

You may want to turn off unnecessary appliances first before turning on your air-conditioner. The time spent cooling your house will still be the same even if you lower your AC’s thermostat.

One example of a heat-generating appliance is your stove or oven. The kitchen is one vital heat source inside your house. Make sure you have turned off these appliances when not in use. 

7. House Insulation and Leakages

The insulation and leakages in your house will also affect the time your AC can cool your home. You must seal all sources of air leaks. You should also insulate your house adequately to ensure that cool air does not escape outside. 

Your basement, attic, and open windows are common leakage areas. You must have sealed and insulated your basement’s rim joists. You have to ensure that you have filled the posts in your attic too. You should close all the windows in the attic and basement as well. 

how long does it take for a house to cool down

These areas are all sources of air leaks. Hence, as mentioned previously, inspect your house and seal all these areas. 

Again, how long does it take to cool a house with AC? A 4-bedroom home would take about 3 hours to cool. This length of time is applicable only when your AC is functioning efficiently and your house is well-insulated.

It will take more than 3 hours when there are air leaks and when the house is bigger.

Next, let’s go over some tips in ensuring that your AC is suitable for your house.

Tips for Choosing the Appropriate AC for Your House

Here are some tips you can follow when choosing the right AC for your house:

1. Know Your Home’s Floor Area

You have to know your home’s floor area so that you can choose your AC’s correct size. You can compute the most efficient AC for the size of your home using the Residential Load Calculation. [2]

The centralized AC type for your home will vary according to your zone and your home’s square footage.

Installing an AC that is too large for your home can cause a ‘short-cycle.’ Short cycles will prevent the compressor enough time to dehumidify the area. Furthermore, on and off short cycles will spend more energy, increasing the cost. 

2. Maintain Your AC Properly

Dirty coils and lack of maintenance will prevent smooth airflow and adequate cooling. Hence, maintain your air-conditioner correctly by cleaning it regularly. 

A worn-out motor and low refrigerant can also prevent your AC from working efficiently. Change your filter regularly too. 

If nothing of these methods would work, you could replace your air conditioner. A malfunctioning AC can cost you hundreds of dollars monthly. 

You also have to schedule HVAC maintenance at least annually. This way, you will know that your AC has all its parts functioning efficiently.

3. Know What Temperature Your Household Members Prefer

The most recommended temperature for households is room temperature at 20 to 25 degrees C (68 to 77 degrees F). Nevertheless, your choice must depend on the preferences of your family. Again, the elderly and infants want warmer temperatures.

Their preferred temperature will help you choose the right AC for your house. Note that choosing a large or small AC relative to your house area is not cost-saving and practical.

4. It Usually Takes 30 Minutes to Lower the Temperature by 2 Degrees

It will take 30 to 40 minutes for an AC to lower a medium-sized home’s temperature to 2 degrees. This data applies assuming that all systems are working well.

The most reliable way to choose a suitable aircon is to consult a professional AC technician.

Conclusion – How Long Does It Take to Cool a House with AC?

The amount of time needed for your house to cool depends on a variety of factors. Typically, it would take three hours to cool a 4-bedroom home. You must insulate your house properly with no air leakages.

How long does it take to cool a house the first time the air conditioner is started? It takes from 3 to 4 hours to cool your house from the time the air conditioner is turned on. If you have installed the AC correctly, you will have the same cooling time for your house.

The AC can take a few minutes to crank up. However, the time does not vary so much. As soon as you plug and turn the AC on, it will start cooling the house.

Choose the most appropriate AC for your home, and you would enjoy the comfort of a relaxed atmosphere without paying high energy costs.