This HVAC size and load estimator, also referred to as a BTU calculator, offers a precise real-world heat load estimate for both heating and cooling.
Additionally, it makes equipment recommendations for your home's heating and cooling system type and estimates the cost of installation, including labour and materials!
Our algorithm for calculating BTUs is unique and DOES NOT over-specify the unit capacity. In order to sell you more expensive equipment, the majority of online tools estimate your home's heat load higher than you actually need.
How to Save Money on Home Heating and Why to Use a Heat Load Calculator
A few BTU heat load calculators are available online, but many homeowners are still unsure of the ideal heating and cooling system for their home.
Here, our new algorithm can provide a wise suggestion that takes into account the system capacity (for heating and cooling), the right kind of system, and the cost of the energy and fuel.
PRO HINT: You can significantly reduce the BTU load on your cooling and heating system by improving the insulation in your home (in the walls and attic) and sealing/insulating your air ducts.
Energy cost savings for cooling and heating could reach 15 to 25 percent!
We also advise you to check the results using this lengthy Manual J online estimator IF you intend to use the results of this heat load calculation to guide your purchasing decisions.
Multiple heating/cooling systems: Our calculator can estimate the cost of installing multiple heating/cooling systems in large homes (over 3000 square feet), specifying the largest possible BTU HVAC system or systems and then the smallest size system for the remaining space.
You would require two 60K BTU compressors and a 30K (2.5 Tonne) system if your heat load is 150K BTUs and your maximum residential central air conditioner size is 60K BTUs (5 Tonne).
To provide you with the most cost-effective estimate, the calculator's algorithm will choose the full size system(s) and the smallest needed system to cover the remaining BTU load.
HVAC System Installation Cost Estimate: Based on the cost of the equipment and the national average of the labour, overhead, and profit that plumbers and HVAC contractors charge for each type of system, the tool will calculate the total installation cost for your new HVAC system.
How To Calculate The HVAC Load Accurately
You must enter precise/appropriate information into the BTU load calculator. This tool as closely as it can to a challenging Manual J estimation. In the absence of this, you risk having a system that is either too big or too small.
Step 1 (Climate Region): Using the region map at the top of the calculator, choose your climate region. For instance, choose Region 3 (yellow) if you reside in NYC or NJ. Choose Region 5 (red) if you live in Texas, etc.
Enter the square footage for your home/building or the area you are performing the calculations for in Step 2 (Area Size).
This step is essential for the precise estimation of your HVAC systems' annualised heating and cooling loads! You will notice a significant change in the cooling/heating BTU load if you leave all settings at their defaults and only change the Region from 1 to 5 and back.
Enter the number of rooms or zones where a new heating or cooling system will be installed in Step 3 (Rooms / Zones).
The number of zones is not very important when estimating heat load if you intend to use a Central AC + Warm Air Furnace (ducted) system or a Boiler.
Using this value will help you choose the best kind of ductless mini-split system.
In our DIY mini split installation guide, we also go over the advantages and disadvantages of installing multiple single-zone Ductless heat-pump systems versus a multi-zone system.
Step 4 (Space Height): Choose your home's typical ceiling height. Most of the time, this value should be 8 feet. The VOLUME of your space will, however, be higher if you have high ceilings or cathedral/vaulted ceilings.
Add the lowest wall height and the peak height for cathedral or vaulted ceilings, divide by 2, and you'll get the average. For instance:
The highest point on the ceiling is 12 feet high, and your exterior wall is 8 feet high. If so, your typical ceiling height is 10 feet:
(12 + 8) / 2 = 10
The majority of US homes constructed between 1978 and 2000 will have 4′′ studs with R-13 wall insulation and should have R-38 roof and attic insulation, according to Step 5 (Insulation Grade). Leave this value (Avg. Insulation R-13 walls) at default if it applies to your house.
If your house is more recent and has 6′′ studs, the insulation rating is R-18. Choose the “More than Average” value in this situation.
Unless you live in a “Super-insulated” home, you should generally avoid using the “Very Well Insulated” value.
Choose “Less than Average” or “Poorly Insulated” if your home is only partially insulated.
When it comes to heating, where your heat loss will be the greatest, these two values are particularly important. If cooling is your main concern when installing a new HVAC system, we advise using the “Less than Average” value to avoid oversizing your cooling equipment.
Choose the average number of windows in your home for Step 6 (Windows). Choose “Average Amount” if you have 1 window or fewer for every 8 feet of exterior wall length.
Choose “More than Average” if there are more than 1 window for every 8 feet of exterior wall length.
Choose the proper window/door insulation level in Step 6 (Windows/Doors Air Tightness). Leave this at the default “Average” value in most situations.
Understanding the Results of Your HVAC Load Calculations
We provide estimated heat load (system size in BTU/h) for both Heating & Cooling as well as suggested HVAC equipment type and size, unlike other online HVAC calculators!
1) Cooling and heating load in BTUs – this is the calculated amount of BTUs per hour and TONNES required to heat/cool your space.
2) The best type of heating and cooling equipment for your requirements.
- Projected Heat Load
Based on the data you entered in the calculator and your location, you will receive an approximation of the BTU / tonnes load for your home. Our optimised BTU calculation algorithm yields results for both heating and cooling that are “conservative” compared to what most HVAC contractors and equipment vendors will tell you.
These figures will typically be 20–30% less than “contractor's guestimate”. However, for the reasons mentioned above, we advise using the lower numbers.
2) Recommendations For HVAC Equipment Based On Heat Load
Based on your climate region and other inputs, our calculator tries to recommend the best piece of gear for your specific situation.
The Equipment Recommendation needs to be further explained because every person's situation is unique. A new construction home, where you have complete control over the design and specifications of the type of HVAC equipment that will be used, would be the ideal application for this calculator. However, the majority of US homeowners deal with pre-existing homes, which has some restrictions.
First off, if your home has a duct system, a central air conditioner and hot air furnace will be the most economical option for you. An electric heating coil can be used in place of a furnace in extremely hot climates to provide warm air on sporadic cold days and nights.
A forced hot water boiler with baseboards, wall radiators, or radiant floor heat is the best heating system if you don't have air ducts, and a multi-zone ductless (mini-split) AC is the best cooling system if you do. Both of these systems are affordable and incredibly efficient.
Regions 3, 4, and 5 rarely experience extremely cold temperatures. Winters there are remarkably mild, with low temperatures on average above zero degrees Fahrenheit. Therefore, it is possible to use a high efficiency ductless (mini-split) heat pump system for both heating and cooling. It is the most affordable type of heating and cooling you can purchase.
Ductless heat pumps are capable of effectively cooling and heating your home in ambient temperatures as low as -15F.
You may not need to install an additional heating system, be it a furnace or boiler, because they can provide heating and do so using a relatively low amount of electricity (3–4 times less than electric space heaters), saving you between $7,000 and $12,000 in installation costs.
Ductless heat pumps run on electricity, so they shouldn't be your only source of heating in climate zones 1 and 2, where it gets very cold in the winter and there are often power outages.
Heat Pumps can be used as your main source of heating even in colder climates if you have a backup heating system in place, such as an old boiler or gas or pellet stove, and you can survive without electricity for a few days in the event of a power outage.
The fact that ductless systems are “modular” and operate at the zone level is a significant benefit. Therefore, there is no need to cool or heat the entire house if you spend the majority of the day in the living room. Run just one zone, please. You can switch the living room zone off at night and turn on the zones in your bedroom(s).
Additionally, ductless systems are roughly 2x more efficient than even the most modern, high efficiency central air conditioning systems, meaning your electric bill will be 2x less! In fact, zoning, which is nearly impossible to do with central air conditioning systems, makes the difference even greater than 2x.
* While electricity costs in most southern states are very low (between $0.10 and $0.13 per kWh), in places like California, where they frequently exceed $0.30 per kWh and peak prices can reach $0.50 per kWh, ductless air conditioning and heating systems are ideal because you can only condition the areas of your home that actually require cool or warm air, rather than cooling or heating the entire building.
Pro Hint: If your home doesn't already have air ducts and it's a single-story (ranch or cape) home, you could install the AC and furnace in your attic using flexible, insulated ducts. This is significantly less expensive than conventional sheet-metal ducts, which must be extended from the basement into all of your rooms and installed from there, especially if your home has multiple levels.
When compared to ductless heat pumps, installing central air is significantly less expensive. However, a ductless system will quickly recover the initial out-of-pocket cost difference by saving an average of 40% on operating costs due to the significant efficiency difference!
Sizing Guide for HVAC
To adequately heat or cool your living space, it's crucial to get the right-sized HVAC system for your home or building. The space won't be comfortable if your heating or cooling system is too small because it won't produce enough BTUs.
Oversizing a system will result in you paying too much for the added capacity: Larger systems cost more to install. In the future, you will also have to pay too much in operating expenses (such as gas, electric, or oil).
The majority of residential HVAC/plumbing contractors do not want to take the time to accurately calculate the heat load & heat loss of your home (or specific rooms) using the Manual J method. In order to “cover their bases,” 99% of professionals specify oversized systems, which are more expensive to install and maintain.
NOTE: To cover their bases when determining the heat load and unit size (in tons/BTUs), the majority of contractors and equipment distributors use INFLATED BTU/h values.
To estimate the heat load more accurately and in line with “real-world” conditions, our calculator uses lower BTU/h values for both heating and cooling. Before making any purchases, we do, however, strongly advise that you (or your contractor) perform a Manual J heat load calculation of your home or a particular area!
Use this calculator only for informational purposes; do not use it otherwise.
Cost of HVAC installation
Depending on the local cost of living, different regions have different HVAC installation costs. However, most states' equipment prices are comparable. The prices for central air (central AC + hot air furnace), hot water boilers, and mini-split ductless systems are listed below.
Keep in mind that installing a hot air furnace and central air conditioning can be done either way. You still need a heating system if all you have is central air conditioning. Because they can be stacked, central air and a furnace go together perfectly.
To determine our costs, we use the US average for existing single-family homes of 2300 square feet.
4-Ton, 14 SEER CENTRAL AC COST Costs range from $5,595 to $7,837 for Central Air. A coil of electricity is used to heat the system. includes removing the old condenser and coil from the central air conditioning unit and using the existing electrical and copper connections. An additional $800–1,200 will be needed to upgrade to 16 SEER.
CENTRAL AIR (AC + FURNACE): A 4 Tonne, 14 SEER Central AC system with an 80K BTU, 96% efficient gas furnace costs between $7,976 and $11,171. includes removing the old condenser and coil from the central air conditioning unit and using the existing electrical and copper connections.
BOILER (Radiant Heat): Forced Hot Water boilers range in price from $4,683 to $6,130 for a traditional gas or oil boiler OR $6,934 to $10,623 for a condensing boiler with an integrated tankless water heater, like those made by Navien, Bosch or Viessmann. includes removing the old boiler and using the current water lines and radiators.
A 4-5 zone whole house mini-split system will cost between $13,876 and $18,058. DUCTLESS HEAT PUMPS. Your home can be efficiently heated and cooled using these systems. includes setting up new copper refrigerant lines, a 240V electrical connection, one outdoor compressor, and four to five interior “wall-mounted units. For each zone, floor-mounted, slim ducts, ceiling cassette indoor units will cost an additional $300–400. Analyse local mini-split prices.
Call some of the nearby HVAC installers you are familiar with to get quotes, or use our referral programme to ask family and friends for recommendations or free estimates.
selecting the ideal HVAC system for your residence
To select the ideal heating and cooling system for your home, use the following recommendations.
As was already mentioned, if you reside in a region with a cold climate, we advise getting a gas boiler for heating and a ductless (mini-split) air conditioner for cooling. Going with Central AC + Hot Air Furnace will be less expensive in the short term if you already have ducts.
In some instances, though, a Mini Split will be recommended for both cooling and heating, but the BTU size will vary.
This part is certainly unclear. So let's take a closer look at it:.
Most Mini-Splits are rated according to their ability to COOL. A mini split with a rated capacity of 12000 BTU (1 tonne) will produce roughly 12000 BTU per hour. But these very same devices can also HEAT! Additionally, the majority of higher-end Mini Split units have much greater heating capacities!
For instance, the maximum heating capacity of a 9000 BTU Fujitsu RLS3H (single zone) is 21000 BTU! Therefore, use the COOLING size when selecting the equipment if you live in zones 3, 4, or 5 and intend to install a ductless system throughout your entire home. Most of the time, there will be plenty of heating BTUs on hand!
You need to look more closely at your unit's specifications in Regions 1 and 2. However, the difference between Heating and Cooling BTUs is typically not as great in larger systems (2-8 multi-zone installations). Therefore, in order to achieve the highest efficiency and capacity possible, you will either need to slightly oversize the unit or install multiple Single-Zone units throughout your home.
Get 3–4 free quotes from local HVAC experts if you're unsure which type of heating or cooling system to install in your home.
Mini splits for cold climates: how well do they heat?
Many homeowners are very hesitant to install a mini split heat pump because they want to add an effective heating system that can be used in the winter. After all, their primary function is cooling. The truth is that a mini split heat pump made specifically for cold climates will heat your space in a way that will surprise you; you will be extremely warm and content!
I'll give an example instead of going over all the advantages and disadvantages and possible outcomes. A backup propane boiler (only for days with temperatures below -4F) was installed at New Brook Elementary School in Newfane, Vermont, five years ago, along with ductless heat pumps and solar panels for HEATING and COOLING the building. Many people opposed it because it was an unusual heating option for a school building in this region. Nevertheless, the upgrade was ultimately accepted and continues to operate very effectively today.
This proves that heat pumps are both cost-effective and capable of providing adequate heat in cold climates. Incorporate that with roof-top solar power, and in 5-8 years you'll have free heating.
But you might be without heat if your power goes out! Therefore, if you live in a northern climate and want to use mini-split heat pumps for heating, you should have a backup strategy!
