Air conditioning professionals mathematically determine the proper unit size. In the heat of the summer, one thing's sure to keep you cool and comfortable: a properly sized air conditioner. But buying an A/C unit can overwhelm you as you see all the available sizes, features and brands. The unit size is the most critical. An undersized unit will never cool your home enough, and an oversize unit is nearly as bad. Square Footage Estimations The simple way to calculate a home's air conditioner size is to use a rule of thumb. According to this common but somewhat inaccurate method, you need 1 ton of air cooling capacity for every so many square feet of living space. While there's some dispute over the exact amount, an often-used amount is 600 square feet. A 2.5-ton unit, then, theoretically would fit a 1,500-square-foot home. Sizing Inaccuracies One problem with estimating air conditioning size based on square footage is that every home is different. An average home in Florida, for instance, needs more cooling power than if it was situated in Michigan.

Given that even Energy Star provides a square-feet-to-BTU chart (with 12,000 BTUs equating to 1 ton), the estimation is valid for a homeowner to use -- but illegal for contractors. Never compare your home to a neighbor's similar-sized house. Manual J Calculations To obtain a precise calculation, you must consider your home's unique factors: What region is it in? How good is the insulation? What direction does the house face? Some websites use online calculators to enable you to perform a closer estimate. An HVAC professional can use the Manual J -- an engineering guide that precisely pinpoints the size you need. References Florida Solar Energy Center: How Contractors Really Size Air Conditioning SystemsEnergy Star: Properly Sized Room ACCentral Air Conditioner Prices: Cost Comparison of AC Brands, Sizes, Repair Costs, & High Efficiency Central AC Systems Photo Credits Jupiterimages/liquidlibrary/Getty Images Suggest a CorrectionThe mercury's rising, and unless you've got central air, you could be in for one hot, sticky summer.

We tested seven of the newest window-mounted air conditioners, from 5,450 Btu up to 10,000 Btu—to suit all your home or apartment-cooling needs.portable ac units kmartIf these AC units don't suit your needs, you can always build your own.lg ptac ac unitHere's a review of a popular portable air-conditioner.gambar air handling unitSee also: Appreciating the technological miracle that is air conditioning. This Is What a $100 Kitchen Makeover Looks Like How To Build a Beautiful Bluestone Patio in One Afternoon How to Build a Stylish Firewood Rack 10 Things to Know About Using Chalky Paint Are New All-Purpose Adhesives Better Than Traditional Epoxies? How to Properly Restore the Polyurethane Trim on Your House This Canadian Town Will Give Land and a Job to Anyone Willing to Move

Busted Old Horseshoe Gets a New Life as a Sweet Knife DIY a Dog Toy Out of Empty Soda Bottles​ Home How To Get Rid of Fiberglass SplintersHow much Freon does a five-ton unit hold? A five-ton air conditioner holds around 10 to 20 pounds of Freon. In general, an air conditioner system needs two to four pounds of coolant per ton capacity. However, there are many variables that affect exactly how much coolant a particular system needs. How much Freon does a 3-ton air conditioning unit hold? How do you put Freon into an air conditioner? How do you add Freon to a window air conditioner? Some of the variables that affect how much coolant is needed include the length of the lineset, the diameter of the tubing in the lineset, the operating efficiency of the unit, the size of the evaporator coil and the type of system. Most units come fully charged and only require additional Freon to be added if the system develops a leak. How do I know if my air conditioner needs Freon?

If an air conditioner is not cooling as well as it once was, it may need Freon. Some signs of this include the air conditioner being turned up to the highe... How much Freon does my truck need? Most vehicles need 25 to 35 pounds per square inch of Freon on the low side if the vehicle is running with the air conditioner on its coldest setting and f... Car Parts & Maintenance Do window air conditioners need Freon? Most window air conditioners do require Freon in order for them to work properly. There is a type of Freon referred to as R-22 or HCFC-22, and it was most ... What is an air conditioner coil? An air conditioner coil is the part that turns a liquid chemical such as Freon into a gas and absorbs heat while creating cool air. The coil functions as a... What is the electricity usage of a geothermal heat pump? Are Merv air filters positively reviewed? Where can you buy a Comfortmaker furnace? Are reviews of Peterson gas logs generally positive?

Where can you purchase Intertherm heater parts? Is it cost-efficient to replace your gas furnace with a heat pump? IP address: 54.214.155.26Time: 2016-09-29T14:31:34ZURL: http://www.youtube.co.id/watch%3Fv%3DUhwHZp-Lymc%26feature%3DrelatedRheem Pro Partners Can Help You Find the HVAC System for Your Home! The typical new home gets a heating and air conditioning system that's about two times too large. Look, I've  discussed oversized air conditioners many times before. Most HVAC contractors use a rule of thumb that says they should put in one ton of air conditioning capacity for each 500-600 square feet of conditioned floor area. New homes, though, typically need one ton for each 1000 or more square feet of floor area. So the typical system's too big, as you can clearly see in this photo I took in Texas on a recent trip. (And that's just the AC for the garage!) Turns out, an oversized system is good, in a perverse way.Because the typical duct system is too small, has too many kinks, is made up of too much flaccid flex, and just generally can't handle all the air from the oversized system.

In many cases, though, it moves enough air to keep the house comfortable. It also provides some cushion, or elasticity, so that the HVAC contractor can get away with installing it that way and having it work OK, sort of. Why this doesn't fly with high-performance homes In a high-performance home, the system is designed to be as close to the right size as possible. That means the ducts have to be designed and installed correctly, too. But the thing is, there's not much buffer in this case. The cushion and elasticity are minimal here so that the system can do its job as well as it can. That means evening out temperature spikes and removing more moisture in humid climates. What happens in a high-performance home if the design has an incorrect assumption in one place? Or if the flex duct wasn't pulled as tight as it should have been? Or when the contractor doesn't use rigid elbows? Or the builder uses wood grilles, with their much lower air flow? I'll tell you what happens.

That system that was supposed to live happily on the good side of the razor's edge slips onto the underperforming side, and it's a bloody mess. How do I know? We do HVAC design here, and we've had a couple of cases where these things have happened. Thou shalt commission thy ducts! The thing is, the distress of unhappy homeowners can be avoided easily by spending a few hours commissioning the system to make sure not only that the equipment is working but also that the duct system is moving enough air. If you're an HVAC contractor and you're not already commissioning every air conditioning system you install in a high-performance home, you're going to face those callbacks. To avoid that, you may need to add some tools and techniques, but the heartache—and money—you save later on will make it worthwhile. Here's what you need to do with every system: Measure the temperature drop across the evaporator coil. It should be within the manufacturer's spec's, which is generally 15-20° F.

Measure the total external static pressure. This tells you if the blower's able to do what it needs to do. It's like blood pressure and shouldn't be too high or too low. Measure the total duct leakage. Even if the ducts are inside the building enclosure, you can have distribution—and comfort—problems if there's a big leak somewhere, as we discovered in one project. Measure the air flow from all the supply vents. In the photo above, I'm doing that with a powered flow hood (the FlowBlaster from the Energy Conservatory). Measure the air flow on the return side. If the sum of the supplies doesn't match the total return air flow, something's wrong. Check the mechanical ventilation system. Some configurations have the outside air being dumped into the return side of the air handler unit. If that's the case, there should always be an electronic damper with a controller in the duct to the outside to prevent the air handler from from pulling in outside air during times when it's not supposed to.

If it's simply a duct running from outside to the return plenum, the damper and controller are almost always there, but I've seen some ERVs installed without these necessary components. (More about this in a separate article later.) Measure the mechanical system air flow. If the ventilation system is supposed to bring in 100 cubic feet per minute, 30 minutes per hour, how do you know it's really doing that if you don't measure it? And if you're installing a balanced ventilation system (ERV or HRV), how do you know it's balanced if you don't measure? Look for pressure imbalances in the house. Bedroom doors get closed at night. What happens to the air if those rooms have only supply vents? There should always be a way for air to get back to the system when doors are closed. If the house is going for certification in the ENERGY STAR new homes program, all this stuff, and more, is required now that Version 3 is out. Not every high-performance home you come across is in a program like this, however, so it's just a good policy to understand the nature of your projects and protect yourself from future heartaches by doing it right from the beginning.