Proper AC installation begins long before anything is actually installed.
The reason is simple: ductwork, electrical capacity, and size are essential considerations. A small mistake may lead to higher power bills and frequent repairs, not to mention shortening the lifespan of a brand-new system.
Evaluating your home should take priority, rather than just “swapping a box” and calling it a day. There’s a lot to look at and consider, but the effort is worth it, especially if stable energy pricing and temperature control are high on the list of priorities.
Think of it as a long-term investment. A correctly sized, evaluated, and installed high-efficiency unit can cut cooling costs by a significant amount.
Why Preparation Before AC Installation Matters
Performance, energy efficiency, and long-term reliability are the most important factors, with a few subfactors to consider as well.
AC installation, whether it’s a brand new system or an air conditioner replacement, is pricey. Doing things right the first time, with a proper and thorough evaluation, will bring long-term value to your investment.
Performance
The proper duct sizing, cleanliness of existing ducts, and placement make sure that each room in your home reaches and maintains the set temperature. You’re looking to avoid weak airflow, noise, and uneven comfort.
Energy Efficiency
Correctly sized and installed, a high-efficiency unit can cut cooling costs, while good drainage design and clearances will adhere to manufacturer requirements and avoid several potential maintenance headaches. It’ll also prevent significant energy loss, most of which will dissipate in the attic or crawlspaces, where it does no one any good.
Long-Term Reliability
Solid work in the evaluation stage will make sure the system runs efficiently, reducing breakdowns and stress. Good drainage and clearances avoid corrosion, water damage, and repetitive maintenance issues.
Without further ado, here are the 5 most important factors to check before an AC installation.
1. Inspect Your Ductwork and Ventilation System
This should be part of a regular AC maintenance routine as well, but it’s even more crucial before a new HVAC installation. Where the air travels, and its ingress/egress points, matter as much as where it comes from.
Inspect Supply Vents and Registers
Remove vent covers and shine your flashlight inside to check for dust build-up, debris, mold, or blockages. Feel the airflow with your hand (or use an anemometer, if you have one) at each vent while the current system runs briefly. Uneven flow signals an issue somewhere upstream.
Check Air Handler and Main Duct Connections
Light up your favorite incense scent and open the air handler cabinet. Observe the smoke near the intake vents and duct joints. Smoke pulling in or blowing away indicates leaks. Visually inspect the connections for any gaps, loose fittings, or damaged seals.
Examine Accessible Duct Runs
You may have to do some climbing or crawling to access most of these, but it’s worth looking over. Check for sagging, tears, moisture, or mold. If you find any wet spots, these are indicators of condensation issues.
Test for Leaks and Blockages
Light your incense up again and run the HVAC blower. Hold the incense near seams, joints, bends, and transitions. Look for erratic smoke. Probe any visual blockages gently and clean or remove if able.
Document and Prioritize Repairs
Break out your smartphone and start snapping pics, note the locations, and measure the airflow differences. Seal minor leaks with mastic or foil tape. For major issues, such as mold or extensive leaks, call a pro for cleaning, replacement, and pressurization testing.
Some of this may not be accessible, so it’s important to contact professionals rather than risk your safety or the safety of others.
2. Check Your Home’s Electrical System Requirements
This isn’t as difficult as it sounds, but you definitely need to contact a licensed electrician for detailed calculations or upgrades. Always remember to cut the power at the main breaker before inspecting the internals.
Locate and Identify Panel Capacity
Begin with your main breaker. Open the panel and check the main breaker or label for amps. 20 breaker spaces typically mean 100A, 30 spaces 150A, and 40 spaces 200A.
Calculate the Current Load
Note all of the major power hogs throughout your home (AC, fridge, electric oven, dryer, water heater, EV charger, etc.), and find the amps for each.
If all you have is watts, divide watts by 240 volts (dryer) or 120 volts (water heater) to get the amps. Split your continuous load (anything that runs for three hours straight) from the non-continuous load. Add all of your continuous and non-continuous up in separate categories.
Multiply the continuous load number by 1.25, and the non-continuous load stays as is. Now, add your continuous and non-continuous loads together (total demand). Take your panel’s amp rating and multiply it by 0.8 for safe, max use. If your total demand is under that, you have room to grow. If it’s over, it’s time for an upgrade.
Check Available Circuits and Wiring
Count your empty slots on the breaker. These serve as potential new dedicated circuits. Inspect wires for size, corrosion, or aluminum (upgrade needed). Verify grounding and double-pole breakers for 240V loads.
Test and Document
Use a multimeter (fairly cheap at a local hardware store) to check voltage at outlets and the panel under a light load. Take a picture of the panel and note the model and age. For AC installation, make sure 125% of the unit’s max amps are available per the NEC.
The whole idea behind DIY checks is to cover the basics before AC maintenance or installation. Professionals will use load meters for precision calculations and compliance with code.
3. Evaluate Indoor Air Quality Before Installing a New AC
Whether you’re looking at ductless AC installation or central air installation, the importance of indoor air quality can’t be emphasized enough. This stage of the process will help you uncover mold, dust, or poor ventilation problems before bringing in the new AC.
Prep and Tools
Turn off the HVAC system and get all the basic tools together, including flashlights, a hygrometer, the incense again, and an optional IAQ monitor if you can get your hands on one.
Visual and Odor Inspection
Check each room, the attic, the basement, and any accessible vents. Look for mold (black/green spots), dust bunnies, or dampness. Sniff around for musty or chemical odors. Check your filters for black mold or clogs.
Check HVAC Components
Replace any dirty filters and have a look at the evaporator coils, checking for slimy moisture. Check the ducts for visible dust, debris, or mold. Use the smoke test at joints and vents for leaks.
Test Airflow and Humidity
Run the HVAC fan and feel the vents for even flow throughout the home. Measure the humidity in each room with the hygrometer. High humidity (60%+) is a haven for mold.
You can get really in-depth with mold test kits or radon/Co detectors, but the pros will typically cover these, as well as conduct blower door/duct blaster tests or full IAQ sampling.
4. Make Sure the System is the Right Size for Your Home
An undersized unit will inevitably lead to short cycling, high humidity, and inefficiency, with early failure high on the probability list. Unless you’re a licensed professional, this is not a DIY project. Professionals will perform what is called a Manual J load calculation, much more precise than the DIY square footage game.
However, you should follow a step-by-step process.
Measure Home Details
This includes room-by-room square footage, ceiling heights, window/door sizes, types, and locations, and wall/floor materials.
Assess Insulation and Air Leaks
This is where some of the DIY work comes in handy. Professionals will check R-values and air sealing throughout.
Factor Climate and Occupancy
Example: Baton Rouge, Louisiana, or South Florida would require a dehumidification focus. Higher occupancy means additional heat, while appliances and lighting are considered as well.
Run Software Calculation
Using ACCA-approved tools, pros will calculate BTU load and divide by 12,000 for tons (example: 36,000 BTU = 3 tons).
Verify with Manual S/D
Basically, this means double-checking that the actual AC equipment installation and duct setup match the heat load number calculated in the (Run Software Calculation) section above.
It’s important to use professionals for this step, as it can be precise, and you want to make sure it’s done right the first time, with everything properly calculated before any kind of central air or ductless AC installation or replacement is performed.
5. Review Space, Location, and Installation Access
It’s not a matter of aesthetics. The location must match what’s optimal for the home, and there needs to be 2 to 3 feet of clearance on all sides of the outdoor unit for circulation, access, and preventive maintenance in the future.
Techs will need 3 feet of access to service panels because tight spots elevate risk, and installation delays are possible if workers are fighting a tight spot. Obviously, it’s best to keep the exterior unit/compressor away from bedroom windows or debris-prone areas (directly beneath trees).
Lastly, installation has to comply with local codes, pass inspection, and protect warranties.
Frequently Asked Questions (FAQs)
How do I prepare my home for AC installation?
Prepare your home for AC installation by cleaning indoor/outdoor install areas, verifying panel capacity, inspecting ducts for debris, moisture, mold, and leaks, and planning for drainage access by clearing condensate paths and providing for attic/basement entry.
Should ductwork be replaced before installing a new AC?
Ductwork doesn’t have to be replaced before installing a new AC. Replace if it’s over 20 years old, is leaky or damaged beyond basic repair, is undersized for the new unit, is moldy and/or improperly cooling, or otherwise fails a professional duct test.
How long does AC installation take?
AC installation typically takes 4 to 8 hours, assuming it’s a standard, central system replacement. New ductwork, electrical upgrades, complicated access, or very large homes may require more time.
What size AC does my home need?
The size of the AC your home needs depends on a Manual J load test performed by a professional, calculating your home’s BTU needs based on the quality of your insulation, windows, climate, and the layout of the home. In general, 1,500 to 1,800 sq. ft. homes end up around 2.5 to 3 tons.
When is the best time to install a new AC?
The best time to install a new AC is during the spring or fall, since off-season installs often mean lower prices, better rebates, and more flexible scheduling.
The Key Takeaways
There’s a good deal of work to cover before an AC installation, but every bit of it will pay off later down the road. The goal is to maximize the efficiency of your new system, extending its lifespan and saving homeowners money in the long term.
These steps are very important towards achieving that goal, and ductwork, electrical capacity, sizing, and IAQ should all get a thorough once-over before an air conditioner installation. Besides, it’ll also provide some peace of mind, which is a good thing to have before the big installation day arrives.
If you’re ready and willing to dive into a serious AC maintenance, central air installation, or ductless AC installation project, you want the best at your back. Contact American Air Cares for expert AC installation, inspections, and advice!
