HomeOffices & BuildingsSystems & ComponentsClimate Control While many large in-plant office installations will be integrated with centralized HVAC systems, smaller buildings are typically outfitted with wall mounted climate control units. PortaFab will specify the proper unit for your space and then provide wall panels with aluminum-framed cutouts to accommodate the system. These units are typically purchased along with PortaFab's electrical package to ensure that the in-plant office is properly wired. Air Conditioning & HVAC Systems Standard air conditioning options include complete HVAC systems or air conditioning only systems. Framed cutouts are available for those who want to install their own systems. To help you estimate the properly sized unit, refer to the following chart that is based on a room with normal insulation and two person occupancy. 6000 BTU A/C unit. 11,600 BTU combination heater/AC unit. Larger office structures can be integrated with centralized HVAC systems.

Area to Be Cooledin Square Feet Example: 20’ x 40’ office = 800 square feet 5 people will occupy the office Using the chart, 18,000 btu/h are recommended + 500 btu/h for each person over two(3 x 500 = 1,500 btu/h.) Total needed for 800 square foot office with 5 people: 18,000 + 1,500 = 19,500 btu/h Although HVAC units are available in the above mentioned sizes, it is better to supply two units half the size located at either end of the building to provide more even distribution. Baseboard heaters provide a cost effective alternative for some modular offices. The most common way to heat a modular office is to include a combination heater/AC unit.  Baseboard heaters, however, can also be used.  To specify your heating requirements, you can estimate that you will need 7 watts of electric heat per square foot of floor space for a unit with an 8’ ceiling height. The number of watts calculated x 3.4 = total btu’s. Example:16’ x 16’ office = 256 square feet256 s/f x 7 watts = 1,792 watts1,792 watts x 3.4 = 6,092 btu/h

The amount of ventilation required in an office or building is based on the application of the room as well as the number of expected occupants. For example, a smoking enclosure would require more ventilation than a regular office. The design requirements will either be listed as: Cubic Foot Requirements – A fractional formula based on .15 cubic foot requirements. Example:12’ x 12’ x 8’ ceiling = 1,152 cubic feet1,152 c/f x .15 = 173 CFM’s Air Changes Per Hour Example:How many air cleaners are needed to substantially remove cigarette smoke from a 28’ x 40’ office with a 14’ ceiling. 28’ x 40’ x 14’ = 15,680 cubic feet Determine volume of air to be circulated each hour (e.g 10 air changes per hour would substantially reduce the smoke) 15,680 c/f x 10 air changes/hr 156,800 c.f./hour/60min/hr = 2613 c.f./minute Determine # of air cleaners needed. (Desired Circulation – Air Cleaner Capacity) 2,613 CFM – 1,000 CFM = 2.6 (2 or 3 units)

Example:A restaurant occupies an average of 50 people. (use the ASHRAE recommended minimum of 35 CFM per person.) installing a split air conditioning unit50 people x 35 CFM per person = 1,750 CFM1,750 CFM/1,000 CFM = 1.75 (1 or 2 units)cost to replace air conditioning belt Due to the fact that climactic conditions vary so much upon regions and location of the building, it is very difficult to estimate the ideal btu’s needed for each application. air conditioner outside unit keeps runningCertain conditions, however, will assist in your calculations: Very sunny area with maximum glass for visibility – 1 ton per 150 s/f Heavily shaded area – reduce capacity 10% Active traffic through door or constantly opening a sliding window – 1 ton per 75-100 s/f

Top Tips for Choosing an Air Conditioner All air conditioners are designed to cool—that is, to remove heat and humidity from interior spaces. If you are in the process of choosing an air conditioner, heed these important considerations before you buy. 4. Central or whole-home units Window units are the most popular air conditioners, and for DIYers, they are the easiest to install and remove. This type of air conditioner fits in a window opening and vents to the outside. Through-the-wall units are larger and heavier than window units. Rather than sitting in a window, a through-the-wall unit rests within a weight-supporting air conditioner sleeve set into an exterior wall. Electric circuitry must be reviewed, especially in older homes, because these units often require greater amperage and voltage. Versatile by design, portable air conditioners—ideal for windowless spaces—exhaust through temporary ducting and can be moved from room to room. Central or whole-home units cool the entire house at once.

Frequently combined with heating for a complete HVAC system, they are the most expensive option and typically require expert installation. Cooling Capacity of the Air Conditioner Air conditioning capacity is measured in units called BTUs. A small window air conditioner can deliver as few as 3,000 BTUs, while a through-the-wall unit can exceed 20,000 BTUs. Room size is perhaps the most important factor in determining the size of air conditioner you need, but consider also: 1. The number of windows in the room 2. The room’s exposure 3. The quality of room insulation 4. Other appliances that may be in use 5. The number of people in the room Consult a handy BTU calculator to figure out exactly how many BTUs your air conditioner should have to keep your space cool. Energy efficiency is measured by the Energy Efficiency Ratio rating (EER)—the ratio of the cooling capacity in BTUs per hour to the power input in watts (the higher the EER rating, the more efficient the air conditioner).

Air conditioners, especially older units, are among the most expensive appliances to run. Choosing an appropriately sized unit is critical, because a unit that is too small will not meet your cooling demands, and one that is too large will cost more to run and will not properly control humidity. In making your decision, first identify units capable of adequately cooling your space and then purchase the one from that group with the lowest BTU capacity and the highest EER rating. When and How to Buy During the summer, air conditioners are an in-demand commodity, which means they are in short supply and consequently more expensive. You’ll save money if you buy during the off-season, when manufacturers frequently offer rebates. As well, some municipalities and utility companies offer rebates on units with minimum EER ratings. And if you opt for central air, you may qualify for a tax credit to offset the purchase of an efficient whole-home HVAC system. In general, your best bet is to buy before summer, and remember to look for a warranty.