HVAC Buying Guide 2026: Choosing the Best Heating & Cooling System

Updated October 2026

The right HVAC system for your home comes down to three things: whether you have usable ductwork, how much heating and cooling your home actually needs, and your climate. Homes with good ducts usually do best with a central split system or a packaged unit, while homes without ducts, additions and single rooms are better served by ductless mini splits. From there, size the system with a load calculation, meet or beat the federal SEER2 minimum for your region, and confirm the refrigerant and installation requirements before you buy.

This HVAC buying guide walks through each step, from system types and sizing to efficiency ratings, refrigerant rules, installation and brands. Ready to browse? Shop all HVAC systems.

What Is an HVAC System?

HVAC stands for heating, ventilation and air conditioning: the equipment that controls your home's temperature, airflow and humidity. Most systems share the same basic parts:

• Outdoor unit: an air conditioner condenser or a heat pump.
• Indoor unit: an air handler, or a furnace with an evaporator coil.
• Ducts or refrigerant lines: ducted systems move air through ducts; ductless mini splits run refrigerant lines to indoor units in each room.
• Thermostat or controller: where you set temperatures and schedules.

If your system is 10 to 15 years old or more, can't keep up, or is driving up your energy bills, it's worth pricing a replacement.

Types of HVAC Systems

Central split systems

The most common setup in U.S. homes. An outdoor condenser or heat pump connects by refrigerant lines to an indoor air handler or furnace, and conditioned air travels through your ducts. If your ducts are in good shape, it's usually the simplest way to heat and cool the whole house. Browse central split systems, including Goodman and MRCOOL systems.

Ductless mini splits

An outdoor unit connects to one or more wall- or ceiling-mounted indoor units, and each one controls its own room or zone. There are no duct losses, and most mini splits use variable-speed inverter compressors. They're a strong fit for additions, garages, basements, older homes without ducts and rentals. Shop mini splits or MRCOOL DIY mini splits.

Packaged units

A packaged unit puts all the components in one outdoor cabinet on a slab or rooftop, connected to your ducts. It's a practical choice when there's no indoor space for a furnace or air handler. See HVAC packaged units, including Goodman packaged units.

Geothermal heat pumps

Geothermal heat pumps are among the most energy-efficient heating and cooling options available. They exchange heat with the ground through buried piping loops. Most residential units are water-to-air heat pumps that deliver air through ductwork, like the MRCOOL GeoCool upflow, downflow and horizontal models we carry. The trade-off is the upfront cost of the ground loop. Browse geothermal heat pumps.

Still deciding between ducted and ductless? Our mini split vs. central air guide compares them in detail.

Heat Pump or AC With a Furnace?

A heat pump heats and cools by moving heat instead of burning fuel, which makes it efficient, especially in mild and moderate climates. Cold-climate models go further: MRCOOL rates its Hyper Heat 2nd Gen central system to heat down to -22°F (see our VersaPro vs. Hyper Heat comparison). An air conditioner paired with a gas furnace is the other common setup; the furnace needs a gas line and proper venting. Our heat pump vs. AC guide covers the trade-offs.

How to Size Your HVAC System

HVAC capacity is measured in BTUs, and 12,000 BTU equals 1 ton of cooling. An oversized system short-cycles, which hurts humidity control and adds wear. An undersized one runs constantly and never quite reaches the set temperature.

• Single rooms and zones: square footage is a reasonable starting point. On MRCOOL's ratings, a 12,000 BTU mini split covers about 500 sq ft. Our mini split sizing guide has the full chart and adjustments.
• Whole-home central systems: square-footage rules of thumb are only a rough guide. Have an HVAC contractor run a Manual J load calculation, which accounts for insulation, windows, sun exposure, air leakage, ceiling height and your local climate. Have the existing ducts checked too, since leaky or undersized ducts undercut even a correctly sized system.

SEER2, EER2 and HSPF2 Efficiency Ratings

SEER2 measures seasonal cooling efficiency, EER2 measures cooling efficiency at peak heat, and HSPF2 measures heat pump heating efficiency. Higher numbers mean lower operating costs. These ratings replaced SEER, EER and HSPF on January 1, 2023, under a Department of Energy test procedure with more realistic ductwork conditions, so the new numbers run a little lower for the same equipment. For example, 15 SEER under the old test is roughly 14.3 SEER2.

Since January 1, 2023, new split central air conditioners must reach at least 13.4 SEER2 in northern states and 14.3 SEER2 in the South and Southwest, with an added EER2 requirement in the Southwest. Split heat pumps need at least 14.3 SEER2 and 7.5 HSPF2 in every region.

Compare the certified rating for the exact outdoor and indoor combination, listed under its AHRI reference number, rather than a brochure's "up to" figure. Our SEER vs. SEER2 guide goes deeper.

A note on incentives: the federal 25C tax credit for heat pumps and central air conditioners ended for systems placed in service after December 31, 2025. Check your state energy office, your local utility and the ENERGY STAR rebate finder for current rebates.

Refrigerant Rules: R-454B, R-32 and R-410A

Since January 1, 2025, new residential and light commercial air conditioning and heat pump systems must use a refrigerant with a global warming potential under 700, under the EPA's Technology Transitions rule. Most new systems use R-454B or R-32. Systems built entirely from components made or imported before January 1, 2025 have no installation deadline, and existing R-410A systems can still be repaired and serviced.

Most current systems we sell use R-454B or R-32: MRCOOL's newer systems use R-454B, and Goodman's use R-32. Some remaining items still use R-410A, including a few MRCOOL packaged units, coils and air handlers, so check the refrigerant listed on each product page. Neither new refrigerant can be added to an older R-410A system, so the indoor and outdoor units must be matched. Our R-454B vs. R-410A guide explains the transition.

Features Worth Paying For

• Two-stage or variable-speed operation: single-stage systems run at full output whenever they're on. Two-stage systems run on low most of the time, and variable-speed (inverter) systems adjust continuously, holding temperature and humidity more evenly and running quieter.
• Smart controls: look for compatibility with the thermostat you want, or built-in app control (many MRCOOL systems offer it). ENERGY STAR estimates that certified smart thermostats save about 8% on heating and cooling bills.
• Noise: if the outdoor unit will sit near a bedroom or patio, compare decibel ratings on the spec sheets.
• Air quality: filters are rated by MERV, and higher ratings capture smaller particles. Confirm your air handler or furnace accepts the filter you want. Browse HVAC accessories.

Installation: DIY or Professional?

• MRCOOL DIY mini splits use pre-charged quick-connect line sets, so you can install them without a vacuum pump or gauges. You'll still need a properly sized dedicated circuit wired to local code (permits may apply), and you must follow MRCOOL's manual to keep warranty coverage.
• MRCOOL VersaPro and Hyper Heat 2nd Gen central systems are an exception among central systems: MRCOOL's warranty doesn't require a professional installer when its No-Vac Quick Connect line set is used. Without it, a licensed contractor must install them.
• Most other central systems, including Goodman, need a licensed HVAC contractor. Goodman's internet purchase policy offers no warranty on equipment bought online unless a dealer installs it to code.

Most whole-home systems need a dedicated 208/230V circuit, so confirm your panel capacity and breaker space before you order. Home Outlet Direct doesn't install equipment, so line up your contractor or electrician before delivery.

Budgeting for a New System

Equipment cost rises with capacity, efficiency tier and the number of zones. If you hire a contractor, budget separately for labor and extras like line sets, pads, heat kits, electrical work, duct repairs and permits. Check current pricing on each listing. Financing is available at checkout.

HVAC Brands We Carry

MRCOOL

MRCOOL is an American HVAC brand founded in 2014 and based in Hickory, Kentucky. It's best known for its DIY ductless mini splits (now in their 5th generation) and also makes central ducted systems such as VersaPro and Hyper Heat, Universal central systems, professionally installed Olympus mini splits and GeoCool geothermal heat pumps. Warranty coverage varies by series, so check MRCOOL's warranty page for your model. Shop all MRCOOL systems.

Goodman

Goodman, part of Daikin since 2012, makes value-focused central air conditioners, heat pumps, furnaces and packaged units. Its current air conditioners and heat pumps use R-32, and the AHRI-certified Goodman systems on our site run from 13.4 to 19 SEER2. Goodman's factory warranty depends on installation by a licensed dealer to code, so systems bought online that aren't dealer-installed may not be covered. Confirm the terms before you buy. Read Is Goodman a good brand? and Goodman vs. Trane vs. Carrier, or shop Goodman split systems.

Why Buy From Home Outlet Direct?

• Wide selection and competitive pricing on central systems, ductless mini splits, packaged units and geothermal heat pumps from brands like MRCOOL and Goodman. See each listing for current price.
• Free shipping to the contiguous 48 states. Large systems ship by freight, curbside, by appointment.
• Manufacturer warranty and expert support: products ship new with the manufacturer's warranty, and terms vary by brand and series. You can add a protection plan at checkout. For help with sizing and compatibility, call 800-495-0144 or use live chat.

Final Checklist Before You Buy

• System type chosen: central split, packaged, ductless or geothermal
• Capacity confirmed with a load calculation (or the sizing chart for single rooms)
• SEER2 and HSPF2 meet your region's minimum and fit your climate
• Indoor and outdoor units form a matched, AHRI-certified combination
• Refrigerant checked on the product page (R-454B, R-32 or R-410A)
• Electrical capacity verified
• Installation plan and warranty terms confirmed, including registration rules

FAQs About Buying an HVAC System

What SEER2 rating should I look for?

At least the federal minimum for your region: 13.4 SEER2 for split air conditioners in the North, 14.3 SEER2 in the South and Southwest, and 14.3 SEER2 with 7.5 HSPF2 for split heat pumps. In hot climates, a higher rating usually pays off in lower energy use.

Can I install an HVAC system myself?

Some, yes. MRCOOL DIY mini splits are designed for homeowner installation, and MRCOOL's VersaPro and Hyper Heat 2nd Gen central systems don't require a professional installer under MRCOOL's warranty when installed with its No-Vac Quick Connect line sets. Most other central systems need a licensed HVAC contractor, and electrical work must always meet local code.

How much does a new HVAC system cost?

It depends on capacity, efficiency, the number of zones and whether you hire a contractor. Check current pricing on each listing, and get installation quotes before you order if you're using a pro.

How long does an HVAC system last?

Many central air conditioners and heat pumps run 15 years or more with regular maintenance, but climate, installation quality and upkeep make a big difference.

What refrigerant do new HVAC systems use?

Most new residential systems use R-454B or R-32, because new equipment must use a refrigerant with a global warming potential under 700 under EPA rules that took effect January 1, 2025. Existing R-410A systems can still be repaired and serviced.

Can I still get a federal tax credit for a new heat pump or AC?

No. The federal 25C credit ended for systems placed in service after December 31, 2025. State and utility rebates may still be available, so check the ENERGY STAR rebate finder and your local utility.