Begin with the right system type for your home

There are 3 fundamental types of air conditioning and heating systems that are commonly used :


1. "Split System"


Approximately 90% of the homes in the US use this configuration. “Split” simply means that your equipment is split into two main components: indoor and outdoor. The outdoor section is variously referred to as a condenser, condensing unit, or simply the outdoor unit. The indoor section is also called an air handler, (all electric), furnace, (typically gas or oil), or, simply the indoor unit. If you have an air conditioner unit outside your home and an indoor unit (typically in a closet, garage space, or attic with ducting attached to it), then you have split system.

2. "Package Unit"

These systems are used primarily on mobile or modular homes or older homes on a crawl space with the ductwork beneath the floor. Occasionally package units are installed on residential flat roofs with exposed ductwork. The easiest way to determine if you have a package type system (or self-contained as they are sometimes called) is to look outside at your air conditioner.

Package units are generally large and will always have 2 large, square or round ducts connected directly to them. If you notice this, then you have a package unit. Package systems are identified on our site under “package unit” or “mobile home” selection links in blue navigation bar at the top of every page.

* Sometimes, in rare instances, the air conditioning package unit will reside outside with a separate, ducted heating unit inside, but this is very unusual and changes  nothing for our purposes of determining system type.   


3. Ductless "mini split"

These are not referred to as central air conditioners and are normally used in single-room applications such as porch enclosures, bonus rooms, music studios, etc.

This is technically a split system with a wall hung indoor unit connected to an outdoor section via refrigerant lines routed through a 3 inch hole in the wall. Multiple ductless type systems can be purchased to provide whole-house cooling where ductwork is costly, impossible, or prohibitive.

Gas or Electric?

I currently have gas heat but because of the recent increases in gas rates would it be advisable to switch to electricity?

There is an understandable interest in finding an alternative among the millions of homeowners who presently use gas to heat their home. CNN recently reported that the price of heating a home with gas will rise by an average of 58% this winter. This is on top of large increases over the last several winters as well. This increase means that the average fuel bill will rise by over $500.00 this winter and most people simply cannot afford or don't wish to pay these huge increases.

What's the solution? Many people are turning to electric heat or heat pumps for relief. But is this always the right solution? The answer is yes and no. Heat pumps are much more efficient than straight electric heat and will cost less to operate But a heat pump is also an air conditioner so your total cost to buy and install will be higher if you have or desire heating only. The bright side is that if you install an electric furnace you will be about halfway to central air conditioning if you decide to add it later because your electric furnace and ductwork will already be in place. Simply add the proper outdoor heat pump section for a complete central air conditioning and heating system.

Electric heat is the least efficient way to heat your home if your local utility rates are about average for the country. Most homeowners are paying between .09 and .12 cents per kilowatt-hour of electric consumption. The formula for determining the cost of operation per hour for an example 10Kw electric heating element is as follows:

Determine the cost per kilowatt hour from your utility. We'll assume you pay .10 cents per kilowatt hour of electric consumption.(The actual kilowatt hour rate is posted on your utility bill)

Determine the kilowatts per hour of consumption of the heating element. In this case a 10Kw heating element consumes 10 kilowatts per hour. We know that each kilowatt hour of consumption costs .10 cents and we are using 10 units per hour so it follows that:

10 units of power consumed at .10 cents per unit = $1.00 per hour.

If you are considering or have a 15 kw heating element the formula is:

15 units of power consumed at .10 cents per unit = $1.50 per hour.

As you can see, electric heat is not exactly inexpensive to operate. However, in some areas of the country rates as low as .035 cents per kilowatt hour (3 and one half cents) are not uncommon. Let review our operating costs using this considerably lower utility rate for the two heating elements above.

10Kw heating element

10 units of power consumed at .035 cents per unit = 0.35 cents per hour

15Kw heating element

15 units of power consumed at .035 cents per unit = 0.52 cents per hour

As you can see, the total cost to operate these heating elements has been reduced from $1.00 per hour and $1.50 per hour, to .35 cents per hour and .52 cents per hour, respectively. The lower rate represents a 2/3 reduction in operating costs compared to the higher and more common rate of .10 cents per kilowatt hour.

In conclusion, before changing from gas heat to straight electric heat, do the math. Call your local utility or consult your power bill to determine your actual cost per kilowatt hour. Use the formula above to calculate your cost per hour of operation. This will help you make an informed decision and may prevent even higher heating costs from striking your home.

Brand Selection

Choosing a heating and air conditioning brand can be confusing, but a little information goes a long way in making the right choice. Not all brands are right for every person, every time. Price, configuration, and capabilities must factor into the decision. We polled our personal advisors and warranty fulfillment techs and came up with some facts (and opinions) about the various brands we carry that may help you decide:

Ruud / Rheem

Ships from: Southeast and Mid West

In business since: 1950's

Quality: Excellent

Limitations: Pricey in some categories but many heat pump models offer excellent value

Warranty Fulfillment: Average

Pricing points: Mid to upper end

Value: Very good

Name recognition: Well known

Availability: Very good

We have offered the brand for over 7 years and have experienced a very low warranty failure rate on the entire product line. We feel Ruud is a very good value (especially when you are considering a heat pump) and quality is top rated by the leading consumer reporting agency for 7 years in a row. Product offerings are extensive and wide ranging.

Ruud has been about average in terms of warranty part fulfillment. Most customers know either the Ruud or Rheem brand, sister companies with identical product offerings.

Goodman

Ships from: Southeast

In business since: 1984

Quality: About average

Limitations: Limited offerings in mobile home equipment

Warranty Fulfillment: Average

Pricing points: Lower end

Value: Good

Name recognition: Well known

Availability: Mostly very good

We have offered the Goodman brand for over 9 years and have experienced about average warranty failure rates. We feel Goodman is a good value and quality is about mid pack. Product offerings are extensive and wide ranging, much better than most

Goodman has been about average in terms of warranty part fulfillment. Many customers know the brand.

 

Electric Furnace Sizing Calculator






Heating Square Footage Range by Climate Zone
ZONE 1  ZONE 2 ZONE 3 ZONE 4 ZONE 5
20 - 25 Btu's per square foot 30 - 35 Btu's per square foot 35 - 40 Btu's per square foot 40 - 45 Btu's per square foot 45 - 50 Btu's per square foot


Use the lower of the two numbers if your home is well insulated and the higher number if it is older or poorly insulated. (Hint: Use the larger of the two numbers above if you're unsure of your home's insulation)

Simply multiply the appropriate factor above by your home's total heated square footage to arrive at your approximate required heating capacity. For example, if you live in the orange zone, your home is not well insulated, and you have 1500 heated square feet, the equation will look like this:

1500 square feet
X 35 heating factor (from the chart above)
52,500 Btu's required to heat your home

Then, to determine the heating output on a given electric furnace, simply view the heating element Btu options that most closely match your requirement. The electric furnace heating element options are displayed within the electric furnace pricing. Each Kw produces about 3400 Btu's of heat, so the heating output of the various heat strip options are as follows.

Element size Heating output

5kw 17,000 Btu's
7Kw 24,000 Btu's
8Kw 27,000 Btu's
10Kw 34,000 Btu's
12Kw* 41,000 Btu's*
15Kw 51,000 Btu's
17kw* 58,000 Btu's*
20Kw 68,000 Btu's

*12Kw and 17kw options offered only with mobile home electric furnaces

If you need more than 68,000 Btu's we suggest either two electric furnaces with separate duct systems for each, or a gas furnace. Remember that the larger the heating element, the more power it will consume.

Most electric furnaces are offered in 7,000-10,000 btu increments so you just need to get close in terms of sizing. If the furnace you selected is more than 10% below your heating requirement, we suggest you go up to the next size. A little under sizing or over sizing is fine, just don't over size by more than about 20% of your heating requirement, or short cycling can occur which wastes energy and reduces your comfor.

Selecting the proper CFM

You will see various CFM (cubic feet per minute) options within the electric furnace prices. This refers to the volume of air delivered and is normally used for air conditioning considerations. The following is the airflow (CFM) requirements for various air conditioning needs:

800 CFM 1.5 - 2.0 tons
1200 CFM 2.5 - 3.0 tons
1600 CFM 3.0 - 4.0 tons
2000 CFM 4.0 - 5.0 tons


If you intend to add air conditioning at some later point, use these CFM considerations based on a professional estimate of your future air conditioning requirements. Otherwise, if you are considering heating only, simply select the Btu requirement of your home and choose the least expensive or middle range CFM option offered within your heating range (they will overlap somewhat).

If you're still unsure which system size is right for you, please e-mail us or call our toll free number at 1-866-862-8922. An experienced design technician will be happy to assist you. Your home's construction quality and insulation is unique and can greatly affect furnace sizing, so this information is intended to provide a general guideline but should not be the only consideration when selecting a furnace for your home.

 

 

Local Utility Rebate Finder

Call our Personal Advisors with your city and utility company name and we will provide you with any local, state, federal, and utility rebates or incentives that may be available in your area. Only from AC4life. Just call toll-free 1-866-862-8922

Electric Furnace Frequently Asked Questions

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Furnace Sizing Calculator






Heating Square Footage Range by Climate Zone
ZONE 1  ZONE 2 ZONE 3 ZONE 4 ZONE 5
30 - 35 Btu's per square foot 35 - 40 Btu's per square foot 40 - 45 Btu's per square foot 45 - 50 Btu's per square foot 50 - 60 Btu's per square foot


Heating Guide

Use the lower of the two numbers if your home is well insulated and the higher number if it is older or poorly insulated. (Hint: Use the larger of the two numbers above if you're unsure of your home's insulation)

Simply multiply the appropriate factor above by your home's total heated square footage to arrive at your approximate required heating capacity. For example, if you live in the yellow zone, your home is well insulated, and you have 1900 heated square feet, the equation will look like this:

1900 square feet
X 40 heating factor (from the chart above)
76,000 Btu required to heat your home

Then, to calculate the output on a given gas furnace, multiply it's efficiency rating by it's listed input rating to determine the actual Btu output of heat. For example, if a furnace has a listed input rating of 90,000 Btu's and an efficiency rating of 80%, it will produce

90,000 Btu input
X .80 efficiency
72,000 Btu actual output

If the same 90,000 Btu furnace has an efficiency rating of 93% it will produce:
90,000 Btu input
X .93 efficiency
83,700 Btu actual output

For this example, using an 80% efficient furnace, the 1900 square foot home above would require a 90,000 Btu input furnace that produces 72,000 Btu's of heating, which is close enough to the 76,000 Btu's required using the climate heating factor.

Most furnaces are offered in 15,000-20,000 btu increments so you just need to get close in terms of sizing. If the furnace you selected is more than 10% below your heating requirement, we suggest you go up to the next size. A little under sizing or over sizing is fine, just don't over size by more than about 20% of your heating requirement, or short cycling can occur which wastes energy and reduces your comfort

If you're still unsure which system size is right for you, please e-mail us or call our toll free number at 1-866-862-8922. An experienced design technician will be happy to assist you. Your home's construction quality and insulation is unique and can greatly affect furnace sizing, so this information is intended to provide a general guideline but should not be the only consideration when selecting a furnace for your home.

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Insulation Variables

Variables such as your insulation, type and number of windows, number of stories, construction type, etc. will greatly affect the required Btu's per square for both heating and cooling. A general rule of thumb is that if your home is well insulated with newer style windows, you can select the smaller size system that falls within your total square footage.

If your home is two story it will place less of a load on the system in the downstairs area as the second floor acts as additional insulation. If your home is not well insulated, has older style windows, and/or a larger than average number of windows, you will want to select the larger system which falls within your square footage range. The less insulated and more windows within the environment, the more likely you will experience greater air and heat loss.
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Contact Us for More Info

If you're still unsure which system size is right for you, or if you're having difficulty downloading the Air Conditioner Size Calculator, please e-mail us or call our toll free number at 1-866-862-8922. An experienced design technician will be happy to assist you.