Ultimate Guide to
HVAC Systems

You may not realize the value of your HVAC system until the AC goes out
during a heat wave, or there’s no heat on a frigid winter evening.

An air conditioning system consists of an intricate set of interconnected parts. Minor problems can quickly escalate to major failures if left unchecked. From proper installation and operation to maintenance and repair, there is a lot to understand.

In this guide, we’ll help you learn how heating and cooling systems work and to:

  • Properly care for and maintain your system
  • Identify common problems
  • Know when repair or replacement is needed
  • Understand smart HVAC and home automation
  • Select the right system to purchase

Chapter 1
What Are Heating and Cooling Systems

To understand what an HVAC system is, one must look at the fundamental components of a heating system. The three main ones include a heat source, distribution system, and control (typically the thermostat). Since air conditioning units work by moving heat from one place to another, they work in much the same way as heating components.

A heating system consists of:

  • A source, such as a furnace, boiler, or heat pump.
  • Distribution system, such as a radiator or forced air system.
  • Control, to regulate how much heat is distributed and when.
How Heating Systems Work Infographic

Furnaces are identified primarily by the fuel type used (i.e., oil, propane, or natural gas). For boilers, size is a factor with around 20 BTU per square foot suited for warm climates and 50 BTU per square foot preferable for a colder region.1

Boiler efficiency, measured as annual fuel utilization efficiency (AFUE), determines how well it converts energy in fuel to heat over a year. Ventilation is also important to consider. If it’s set up properly with a gas boiler, you can prevent problems such as carbon monoxide poisoning.

Heat pumps have their own unique set of considerations. Used in central heating/cooling systems, they use outside air to provide interior temperature control. A heat pump transfers heat energy from one place to another. A single ground source, air source, or water source pump can heat an entire home.

Air Conditioners

An air conditioner works by removing heat and blowing cool air into a room. A system of refrigeration components extract heat.There are several types of ACs, to accommodate any type of home, including:

  • Window/Room ACs: Install directly in a window; modern units are highly efficient at cooling a single room and can last from 10 to 15 years.
  • Central Air Conditioners: Using a system of supply and return ducts, they circulate air effectively throughout an interior space, and have a 15- to 20-year lifespan.
  • Split HVAC System: An indoor and outdoor unit, such as a furnace/air conditioner, heat pump/air handler, or furnace/heat pump, to regulate temperature. A hybrid split system can be powered with electricity or gas.
  • Mini Split Systems: Last 12 to 15 years, provide zoned cooling, and don’t require ductwork; a ductless mini split system can be installed in a new home or it can be retrofit to update an older residence.
  • Single Stage: The compressor works on one level, with no low or high settings.
  • Two Stage: Works on high for hot days (at full blast) and low for less cooling in milder conditions.
  • Variable Speed: Uses an inverter to adjust motor speed and deliver an appropriate amount of power to the compressor, based on the heating or cooling load.
  • Packaged System: All components are combined into a single unit, typically installed on the roof and connected to an air duct system serving the interior.
Components

The basic components of an HVAC system that you need to know about include:

chap1-1
  • Air Filter: A fine mesh filter that cleans the air of pollen, mold spores, dander, and other small particles before it enters your home to improve indoor air quality.
  • Blower: A motor-driven system, often referred to as an air handler or air handling unit, that transports air through the air conditioning system.
  • Burner: Combines air and gas to maintain an igniter’s flame in a heater.
  • Compressor:Pumps and pressurizes refrigerant in its vapor form, as it circulates from the evaporator to condenser and back.
  • Condenser: Located outside the home, the condenser unit is connected directly to the evaporator coil and cools refrigerant gas via heat exchange, converting it into a liquid.
  • Ducts: Pipes or enclosed chambers that deliver air to each room from an air handling unit. Air ducts are usually made of sheet metal or fiberglass.
  • Evaporator Coil: A series of tubes that transport liquid refrigerant to absorb heat from the air through evaporation. An evaporator unitwith an outdoor or indoor coilcan absorb or add heat to a system.
  • Expansion Valve: Part of the evaporator that controls the temperature of liquid coolant.
  • Gas Valve: Part of a furnace, it controls how much gas is used.
  • Heat Exchanger: Draws in and heats cold air, which is then circulated throughout the home, and transfers heat from hot components to colder parts of a machine.
  • Igniter: The pilot light of a gas furnaceproviding the gas used as fuel.
  • Refrigerant Lines: Heat- and cold-resistant metal tubes that transport refrigerant throughout the AC unit or system, specifically from the compressor to the evaporator coil.
  • Thermostat: A programmable interface that allows you to control an HVAC system; connected directly to it, the thermostat triggersthe system to begin heating or cooling.
  • Vents: Cut into air ducts to let air enter a room; also known as a register, a vent channels air in a certain direction using slatted metal.

HVAC systems also consist of several smaller, yet essential parts likehoses, belts, and electrical connections. Each should be included during care and maintenance, to be covered in chapter 2.

Sources:
  1. https://www.centralhtg.com/blog/what-is-hvac-system
  2. System Types - https://atticareusa.com/ultimate-guide-for-an-hvac-system/
  3. Components - https://atticareusa.com/ultimate-guide-for-an-hvac-system/
  4. Components - https://www.770coolair.com/blog/uncategorized/the-different-components-of-an-hvac-system/
  5. Components - https://www.ac-heatingconnect.com/facility-managers/hvac-glossary-of-terms/
  6. Components - https://en.wikipedia.org/wiki/Glossary_of_HVAC_terms

Chapter 2
How to Properly Take Care of and Maintain Your HVAC System

Proper care and maintenance should be considered on a regular basis. More thorough checks should be done twice a year, preferably in the spring and fall, and performed by a qualified technician. It can help improve and sustain efficiency and reduce bills.

Here are some of the best ways to maintain your HVAC system:

  • Change Air Filters: HVAC filter should be changed every 30 to 90 days, depending on the type and your location. A filter should be checked once a month, which is relatively easy to do; if dirty, clean or replace the filter immediately. Clean filters reduce the work a system needs to do to maintain the desired temperature.
  • Keep Outside Units Free of Debris: Leaves, branches, twigs, pollen, and dirt can collect on top of or around the unit and block ventilation. Peak times include autumn as well as winter when water and ice can cause mold or algae to start growing. In the summer, avoid getting grass clippings on the unit when mowing. Check the unit regularly to ensure there’s two feet of clearance on all sides.
  • Clean Out Clogs: If an AC unit is clogged with buildup, mix bleach with a cup of water and pour it down the condenser drain. If you do this once a year, it can remove mold and algae in the system. Also be sure to check the condensate drain.
  • Inspect the Whole Unit: Check for damage and any hazards throughout the system, especially in the spring/fall before the onset of extreme temperatures. At the very least, perform an inspection once a year.
  • Check Refrigerant Lines: The lines carrying refrigerant into your home can wear out, leak, or become loose, resulting in inadequate pressure and heating/cooling performance. Environmental conditions can affect refrigerant lines any time of year, so check them monthly.
  • Make Sure the Unit Is Level: An uneven, or tilted, unit may not work properly, and it can cause undue stress on components. Even if you’ve placed it on pads, check that they are holding. Level checks should be done every two or three months.
  • Check the Fan Blades: An HVAC technician should do this during a preventative maintenance check. However, you can take a peek from time to time (when blades are stationary and in motion) to check for signs of trouble.
  • Don’t Shut More than 20% of Registers: Closing more will force the system to work harder to provide the desired level of heating or cooling.
  • Be Aware of Odors and Noises: For indoor units, unusual odors and sounds can indicate severe problems that can lead to complete failure if not fixed.

Also, don’t forget to replace the batteries in your carbon monoxide (CO) detector. HVAC systems that use natural gas or oil can emit CO and other harmful chemicals. Maintaining the CO detector will protect you should there ever be a gas leak.

If you’re looking for additional savings:

  • Use a programmable thermostat; added control can cut heating bills at least 10%.1
  • Properly insulate and ventilate your attic for optimal summer cooling and winter heating.
  • Rotate ceiling fans counterclockwise in fall to circulate warm air.

But you should always rely on a professional to:

  • Tighten electrical connections
  • Inspect hoses and belts
  • Lubricate moving parts
  • Measure system pressure
  • Check for leaks
  • Clean evaporator/condenser coils
  • Check refrigerant levels
  • Inspect fuel connections
  • Inspect combustion and heat exchangers
  • Test low-water cutoff and pressure relief valves
chap2
Benefits of a Maintenance Plan

A maintenance plan, such as Nexgen’s X Protection Plan, ensures you benefit from routine service. It also reduces the likelihood of future equipment issues, failures, and emergencies. With a regular maintenance plan, customers usually see the following benefits:

  • Lower Energy Bills: A poorly maintained heating or cooling system is less efficient, which leads to higher monthly energy bills. Your maintenance plan can reduce energy usage, thereby lowering costs.
  • Improved Air Quality: Maintaining an HVAC system enables it to effectively remove dust and mold from the air, improving indoor air quality, making it easier to breathe, and reducing the likelihood of respiratory problems.
  • Fewer Repairs: When a technician spots a problem early on, such as a worn frame belt, a routine replacement can avoid costlier repairs later. Even the best HVAC systems can develop problems, but technicians know early signs to look for and how to fix them.
  • Avoiding System Failures: A catastrophic failure can occur at any time without maintenance. It may occur during a family get-together in mid-winter or a gathering of friends during a summer heat wave. Routine checks can avoid emergency repairs at the least convenient times.
  • Equipment Longevity: If you neglect maintenance, you may end up having to replace your HVAC system within three or four years. Regular upkeep can mean your equipment lasts much longer and that you get a sound return on investment before replacing it.
  • Safety: A short circuit can cause a fire, putting your family in danger, while furnaces can develop carbon monoxide problems if not properly maintained. With a regular maintenance plan, your system will run safely, and your family will be protected.
Spring/Summer Maintenance Checklist
  • Replace air filters
  • Clean condensers and evaporator coils
  • Make sure drain lines are clear and clog-free
  • Check for worn belts/pulleys; replace them
  • Empty drain pans of standing water
  • Look for mold or debris in ducts
  • Recharge refrigerant and check for leaks
  • Look for leaks in the HVAC cabinet
  • Make sure the cabinet door is closed/sealed
  • Remove debris from outdoor units
  • Check thermostat settings
  • Assess operation of the fan motor
  • Check all electrical connections
  • Ensure blowers/blades are in working condition
  • Lubricate moving parts as needed
  • Change any old batteries as necessary
Fall/Winter Maintenance Checklist
  • Change air filters (preferably every 30 to 90 days)
  • Inspect heating elements and obtain service if they are damaged
  • Inspect the ignition burner assembly
  • Have a technician check for gas leaks and test gas pressure
  • Make sure the furnace and flue system are properly connected
  • Replace frayed/damaged belts and pulleys
  • Avoid overflows by clearing drain lines and pans
  • Inspect all wiring and electrical connections
  • Verify the heat pump is working normally
  • Lubricate bearings, motors, and other moving parts
  • Make sure the thermostat is set to the proper temperature
Sources:
  1. https://www.davidleroyplumbing.com/blog/hvac-maintenance-checklist/
  2. Maintenance - https://www.davidleroyplumbing.com/blog/hvac-maintenance-checklist/
  3. Maintenance - https://atticareusa.com/ultimate-guide-for-an-hvac-system/
  4. Professional checks - https://blog.coldwellbanker.com/the-ultimate-homeowners-guide-to-understanding-your-heating-and-cooling-system/
  5. Maintenance plan benefits/checklist - https://www.davidleroyplumbing.com/blog/hvac-maintenance-checklist/

Chapter 3
Common HVAC Problems

If you’ve begun to experience problems with your HVAC system over time, you are not alone. Heating and cooling systems are complex and endure a great deal of stress. But you can prevent excessive wear or damage by identifying common problems such as:

  • Uneven Heating/Cooling: An HVAC system should provide even temperature distribution throughout your home. If it’s not, a blocked or leaky duct may be the cause.
  • Noise: Whining or squealing may indicate a motor problem. If there are other unusual sounds, the problem may be mechanical or indicative of an obstruction of air flow.
  • Refrigerant Leak: If warm air is blowing in instead of cool air, there may be a leak or low coolant in your refrigeration lines. Without enough refrigerant, your AC unit cannot function properly.
  • Drainage Problems: A malfunctioning condenser will cause water to collect inside the unit, potentially causing water damage. The only solution is to replace the condenser.
  • Electrical Malfunction: Wires and terminals can wear out over time, causing compressors or fans to stop working. Replacing electrical components is generally affordable, but should be done by a qualified technician.
  • Dirt: Any part of an outdoor or indoor unit can get dirty. Clean outdoor units with a hose and indoor ones with a vacuum cleaner or microfiber cloth.
  • Long Running Time: If the heating and cooling system takes a while to start, reset the thermostat. Depending on its capacity, your HVAC system may handle a different temperature setting better.
  • Sensor Problems: Thermostat sensors that go haywire can cause an HVAC unit not to start. If the temperature onscreen doesn’t match that of indoor air, the thermostat may need to be replaced.
  • Obstructed Condensers: If the condenser is obstructed or clogged, mold and mildew can grow. To avoid this, remove fallen leaves, branches, or brush near your vents.
  • Obstructed Indoor Vents: Your HVAC system may not work right if indoor vents are obstructed. Move furniture or other items away to allow for proper air flow.
  • Blown Fuses/Tripped Breakers: Your HVAC system may be overworked or improperly sized. A dirty filter may be causing the blower to consume more energy, but a technician should check for other problems as well.

Other issues can occur as well. If an outside vent is spitting out water, it is likely clogged. Unscrew the vent if you can and replace it, or unclog it to let air from the radiator escape. If a hot water radiator won’t heat up, your heaters won’t work either. Using a screwdriver, open the bleed valve, making sure a bucket is underneath to collect the water. Once the air bleeds out, the radiator should work.

Also, if you notice an increase in allergies, it may be due to mold, mildew, or dust in your HVAC ducts. Cleaning ductwork can reduce your symptoms. Allergens can also cause respiratory problems and extreme fatigue, so it’s important to address indoor air quality issues. If dry air is a problem, install a humidifier.

Sources:
  1. https://atticareusa.com/ultimate-guide-for-an-hvac-system/
  2. https://blog.coldwellbanker.com/the-ultimate-homeowners-guide-to-understanding-your-heating-and-cooling-system/
  3. https://www.jenningsheating.com/10-most-common-hvac-problems/

Chapter 4
When to Replace or Repair Your HVAC System

There will come a time when you’re faced with this decision. Oftentimes, you can choose to repair your HVAC system, but an HVAC contractor may ultimately suggest replacing it. System failure is one situation in which replacing it with something newer and more efficient is best. If the unit works too hard to provide the temperature you need, it can break down, not to mention draw excessive power while running.

Uneven temperatures in your home aren’t just inconvenient. They mean your heating/cooling system isn’t working the way it should. When one room is hotter or colder than another, call a specialist to check the system. Perhaps there’s a minor issue they can fix. But if your HVAC system is failing, replacing it is likely the best long-term option.

If there is excessive dust in the air, despite completing regular maintenance such as replacing filters, the system may no longer be able to properly ventilate indoor air. Other serious issues include squealing and grinding noises, while a heating unit that emits odors may have a burnt wire or be leaking toxic fumes. If room temperatures are uneven, immediately seek the advice of an HVAC specialist.

In general, the question of repair vs. replacement can be addressed by considering:

  • Safety: You can repair any valves or wires that malfunction. But if a furnace is cracked, carbon monoxide may put your family at risk. Vapor leaks from air conditioners can be dangerous as well. Replacing the unit is the best option to restore your safety.
  • Repair Costs: The cost factor is often the most pressing for homeowners. Heating and cooling system repairs can be expensive, especially with frequent service calls. If the repair bill would be more than half the cost of your system, replacing it is generally the most cost-effective option.
  • System Age: HVAC systems from 15 to 20 years old are more prone to malfunctioning and failing. Check your product documentation or bill for when it was installed or, if a previous owner installed the system, check whether the installation date is written on the unit. The date is often in the front. If you don’t see it, look for the unit’s serial number on the chamber door and call the manufacturer; they can probably tell you the installation date.
  • Energy Consumption: Older HVAC units and systems tend to use more energy. If your system isn’t running as well, or you notice your monthly utility bills rising, consider a replacement as well as investing in better insulation or energy-efficient windows. Half your household energy is used by your HVAC system. If it consumes any more, a newer or smaller unit may help lower utility costs.
  • Reliability: Do you constantly have to adjust the thermostat to stay comfortable? It’s probably time for a new heating and cooling system.

Maintenance will help your HVAC system last longer. However, one day there will be a decision to repair or replace it. Considering the factors above will help make a choice that can have positive impacts on your wallet, and comfort, for years to come.

Chapter 5
Smart HVAC and Home Automation

Smart home technology isn’t limited to lights you can turn on from the couch or TVs that let you browse the internet. Personal assistants that let you listen to music or play games are all the rage. But did you know smart HVAC systemscan provide real functional value for your home and help you save money? If you have central air conditioning and heating, you can benefit from the following capabilities of a Smart HVAC System:

  • Seasonal Control and Variation Dampening: Daily and seasonal temperature fluctuations can be hard on your HVAC system. Variation dampening can provide individual rooms with more AC flow. It works automatically in a smart system, so you don’t need to keep changing the settings on your thermostat. Temperatures can fluctuate significantly during a northern winter, while the hot, humid summers of the South can be hard on the AC and your family. With precise control, you can direct heating, cooling, and energy to the rooms being used.
  • Refined Temperature Control: Chances are, each person in your home has their own temperature preferences. Your spouse may prefer it cooler, while the same setting may leave you shivering. A smart home system lets you control the temperature in each individual room. Natural temperature variations can occur from room to room, especially if some have more sun exposure and others are shaded. Temperatures may vary throughout the day too. For example, rooms receiving heat from the sun at certain times require less cooling. A smart system can automatically adjust for that.
  • Increased Convenience and Control: Your HVAC system can be controlled from your phone or by using your digital personal assistant. This is a step up from a window unit with a remote control. You can use your smart system to turn the A/C on and off remotely, even if you’re not home, and set it to a schedule. Some smart systems incorporate temperature, humidity, light, and even motion sensors for the ultimate in automation. There’s even a temperature controller that tracks your local weather!
Smart HVAC Components
Nexgen Smart Vent
  • Smart Vents: A smart vent in each room can be controlled from a thermostat, personal assistant, or your phone.It allows the thermostat to more precisely controlthe temperature from room to room.Installing one in your bedroom can mean having just the right amount of air flow to get a good night’s sleep. Some smart vents on the market include filters to provide fresh air.
chap5-1
  • Smart Thermostat: Eliminates the hassle of constantly adjusting a manual thermostat. Able to learn your personal habits, a smart thermostat can run the central unit on an appropriate schedule. Some units remain connected to your smartphone. This means you can not only monitor and control the system remotely; the thermostat also can track your location to know when you’re coming home (and adjust the temperature accordingly).
chap5-2
  • Sensors: Allow for more precise control of an HVAC system. A sensor can relay information on a room’s exact temperature and whether it is occupied or not. Sensors can be directly linked with the thermostat; some can even be paired with smart vents. Occupancy sensors add control of smart lighting and home security systems. Depending on the model of thermostat, it may come with a suite of sensors to place in your home where you need them most.

These aren’t the only smart components available. There are smart ceiling fans, some that can sense room occupancy and that combine with smart personal assistants and smartphones. Plus, there are several smart home assistants on the market, including Amazon Echo, Google Assistant, and others that pair well with smart HVAC systems.

Source:
  1. https://ideaing.com/ideas/smart-home-hvac-guide/

Chapter 6
How to Buy an HVAC System

HVAC systems are not one-size-fits-all, so choosing the right one can be challenging. Each system is rated for certain applications and levels of performance. Depending on the size of your home and your heating and cooling needs, you will need to consider several factors. One is the official HVAC ratings that are used. These tell you a great deal about how the system works, and include:

HVAC ratings Infographic

  • AFUE: Average Fuel Utilization Efficiency is used to measure how efficient a gas or oil-fired furnace is. If a unit has a 78% AFUE, it converts 78% of the fuel it consumes into heat. A high-quality furnace may have an AFUE as high as 98.5%.
  • COP: Coefficient of Performance; often used with heat pumps, it compares how efficient a pump (or air conditioner)is at transferring heat to the amount of electricity it uses in the process. For example, if a system has a COP of 2.1, it provides 2.1 units of output for every until of electrical input (ratings range from 1.5 to 4).
  • EER: Energy Efficiency Ratio, which compares output cooling energy in British Thermal Units to input electrical energy in watt-hours. The higher its EER, the more efficient an air conditioner is.
  • HSPF: Heating Seasonal Performance Factor, which is used to measure a heat pump’s heating efficiency. Pumps with higher ratings are more efficient. Energy Star rated units have an HSPF of 8.2 minimum; however, ratings between 7.7 and 13 are sufficient.
  • SEER: Seasonal Energy Efficiency Ratio is the standard for gauging the efficiency of air conditioners and heat pumps. Optimal SEER ratings range from 13 to 30, while an Energy Star rated unit will be rated at least 14.

In addition to ratings, the certification of an HVAC system can tell you a lot about it. In general, you want to purchase heating and cooling equipment that is:

  • Energy Star certified: Energy Star represents a standard in efficiency set by the U.S. government and the Environmental Protection Agency. To earn the Energy Star label, a product must be independently certified and meet strict performance and quality standards while providing a minimum level of energy savings. The Energy Star website provides information on finding the most efficient products, benefiting from available tax rebates, and improving comfort and efficiency at home.
  • HERS tested: The Home Energy Rating System (HERS) measures the energy efficiency of a home. It also identifies areas where efficiency can be improved. Having originated from the California HERS program, it is a requirement in the state and available throughout the United States. A home’s energy efficiency rating is ranked on a scale from 0 to 250 (HERS Index), which is determined by evaluating HVAC systems, vents/ductwork, ceilings and roofs, air leakage, and exterior walls.
Steps for Choosing the Best HVAC System

With HVAC ratings and certifications in mind, and using the insights provided throughout this primer, a step by step approach to selecting the right system is possible. Here is an effective process for finding a system properly rated and sized for your home.

  • Step 1:
    Have Your Ductwork Inspected
    . For the most thorough inspection, hire a professional contractor. A new HVAC system won’t perform at peak efficiency if there are leaks and poorly sealed joints in the ductwork. Air leakage can reduce efficiency by 30%. A contractor can fix any breaks, insulate ducts, and clean dust and debris to ensure your new system is as efficient and reliable as possible.
  • Step 2:
    Find a Furnace
    . Older heating systems are inefficient. An old furnace might have an AFUE of just 56%, while a new one may be 98.5%. When choosing a furnace, pay close attention to the type of air handler. There are single-stage air handlers, but these only have one speed setting, wasting energy to heat your home. Two-stage air handlers let you save energy on a low setting and operate on high when needed, while variable speed (multi-stage) air handlers can run at different speeds to adjust indoor temperature.
  • Step 3:
    Choose an Air Conditioner
    : Select a unit that has a SEER rating of at least 16. Air conditioners with high SEER numbers can save as much as 40% on your energy bill. The best models have variable-speed scroll compressors, which are quieter, and an all-aluminum evaporator coil that’s more resistant to corrosion and leaks than copper and steel coils. A high-performance AC provides reliable cooling throughout your home and air filtration to improve indoor air quality.

When selecting any HVAC unit, compare all ratings, including AFUE, SEER, and HSPF.

  • Step 4:
    Calculate the Total Cost
    : In addition to the initial purchase and installation cost, consider the long-term costs of the system as well. These include utility costs and the estimated lifespan of the system. Also factor in maintenance and repair needs. Investing in a high-efficiency system will cost more up-front. However, it can save you in the long run; and the higher the quality of the equipment, the less you’re likely to spend on repairs.
  • Step 5:
    Research HVAC Contractors
    : Ask family members, friends, and neighbors if they know a reputable contractor, or research HVAC company websites and reviews online. Finding an experienced and qualified contractor is important. If the HVAC system is the wrong size or installed incorrectly, it can waste a lot of energy. A qualified contractor has the tools to calculate the right sized equipment and ensure it runs as efficiently as it was designed to.

For help selecting and installing your home HVAC system, contact Nexgen. We offer same-day installation of air conditioning units and heating systems. For top-of-the-line maintenance and service, join our X Protection Plan at a low monthly cost. Our company is #1 rated for home services in Southern California. For professional advice by a certified HVAC professional, a thorough in-home inspection and assessment, and free estimate, call 833-729-9735 or book your appointment online. We are ready to serve all your indoor heating and cooling needs.

Sources:
  1. Ratings, Steps - https://www.countrysideph.com/blog/choose-right-hvac-system/
  2. COP - https://ee.odec.com/explaining-seer-eer-hspf-cop/, https://www.adams-air.com/houston/what-is-COP.php
  3. EER -https://ee.odec.com/explaining-seer-eer-hspf-cop/
  4. HERS -https://housemethod.com/maintenance/hers-testing/
  5. https://www.energystar.gov/
We are OPEN as a designated essential service & taking extra precautions to serve you safely. 
LEARN MORE >
TAP TO CALL