SpacePak Vs. Unico: Which High Velocity HVAC System Is Best?

Upgraded Home Team
by Upgraded Home Team
Choosing between HVAC systems is tough due to the wide variety of them on the market. Unico can outperform SpacePak HVAC systems, but SpacePak is affordable and effective. Whether it be price or performance, follow along as we compare SpacePak and Unico HVAC systems.

You’ve probably come across the names SpacePak and Unico in your search for heating and cooling solutions. They are the leaders in high-velocity HVAC systems. These systems have a lower profile and require less space than your average air conditioning unit. Their supply tubing is more compact than traditional ducts, and they are often used in older homes that have space limitations.

Not just older homes, though – there’s plenty of new construction taking advantage of the reduced duct size and quick climate control.

When trying to decide on a SpacePak or Unico Hi-V HVAC, the first priority is availability. Many times local companies will only stock one brand. If both are available, Unico is usually the winner. Therefore, we think Unico is ideal since it’s optimal for your cooling and heating solutions.

As always, consult with a qualified technician before making your final decision. Each home is different, and there are many factors that could make one a better choice over the other. In this article, we will take you through both SpacePak and Unico so you can decide which HVAC system is best for you.

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SpacePak Or Unico: Which One Should You Choose?

Like most things in home improvement, the answer can vary. Depending on your area, you might only find suppliers and technicians for either SpacePak OR Unico – but not both. The cost difference is negligible between the two. If both systems are available in the area, we recommend the Unico Small Duct High-Velocity system.

Unlike SpacePak, Unico features a twist fit connection system to help simplify the installation process. The supply ducts connect through lock-and-release tabs, allowing for quicker assembly.

Should you ever want to modify your system, these tabs allow you to keep the process simple. They also sell the supply duct tubing in three-foot sections, allowing quick connections to minimize custom cuts. All tubing is supplied with couplings attached at the factory.

Included Equipment

Both SpacePak and Unico are high-velocity HVAC systems. They come as cooling units with optional heating units that can be added on. These systems are built modularly to suit each individual home, so always double-check with a qualified technician before purchase.

The following is a basic breakdown of what each system will include:

  • Air Handler – The air handler for the system. Installed in the attic or basement.
  • Condensing Unit – Helps to cool the air through heat exchange with the surrounding air. Installed outside.
  • Main Duct Tubing – Carries the main supply of conditioned air from the Air Handler and transfers it to the various supply ducts. Installed directly to the Air Handler.
  • Supply Duct Tubing – Branches off of the Main Duct and takes the air to vents throughout the home.
  • Vents / Registers / Outlets – Round and about 5 inches in diameter. Installed in floors, walls, or ceilings. Specifically, when referred to as “registers” it means that the vent is capable of adjusting the airflow through valves.
  • Refrigerant Lines – These connect the Condensing Unit outside to the Air Handler inside.
  • Drain Line – This connects the Air Handler to a designated drain.
  • Electric Lines – These power the unit and all of its components.

Benefits Over Normal HVAC

Most people are familiar with the large profiles and rattling sounds of regular HVAC systems. Not everyone knows about their slim and quick cousin – the High-Velocity HVAC.

Lower Profile

These systems boast a lower profile and a more efficient and aggressive approach to providing a comfortable room. They remove up to 30% more humidity than conventional systems. This allows for more comfortable environments at a higher temperature.

Easy installation

The supply tubing is easy to install, and rarely requires modifying the existing structure. In both the SpacePak and Unico systems, this tubing is much smaller than a normal HVAC duct and wrapped in special insulation. They are flexible and usually a minimum of 10 feet long to prevent sound issues.

Better Efficiency

Traditional systems might lose up to 25% of their heating or cooling capabilities through leaks. Because of their insulated supply tubing, Hi-V HVAC systems usually lose less than 5%.

Installation Choices

The vents or registers can be installed into floors, walls, and ceilings – allowing them to be well hidden. In combination with radiant flooring, you can keep your home the perfect temperature entirely out of sight.

Climate Control

Both SpacePak and Unico have very similar systems when it comes to climate control. They are modular, with options for hydronic or electric coil heaters, or just cooling if that’s all that’s needed.

It’s a similar setup to older HVAC systems. The HVAC unit conditions the air, then it is pumped throughout the ducts of the house. The primary difference is that in a SpacePak or Unico system, the heated or cooled air is pumped through a high-velocity air handler.

The increased air pressure quickly circulates the air, bringing your home to the desired climate quicker than a standard HVAC. Complex installations can even have precise floor by floor climate control. They do this by installing multiple high-velocity air handlers.


Hi-V HVAC systems are ideal for those older homes where central heating or cooling wasn’t designed in. Both SpacePak and Unico feature small flexible ducts, packed in insulation. These ducts can easily thread through walls and floors where traditional HVAC ducts wouldn’t fit.

The supply tubing is 2 inches in diameter inside and 3.5 inches in diameter outside. It comes in varying lengths and attaches to the main duct line, which has a diameter of 7 to 9 inches. The main duct line is installed in the attic or basement.

The vents or registers are about the size of a DVD, just under 5 inches wide. They can be installed in the floor, walls, or ceiling. The vents and registers come in many designs so you can match your home’s existing decor.

Installation typically takes 5-7 workdays for qualified technicians to complete in your average home. This can vary due to housing size and difficulty of installation, so make sure you ask the installers for a time estimate.


High-velocity HVAC systems do tend to have a higher initial cost, it’s true. Quotes start at $3,000 to $18,000, a very wide range.

It’s challenging to narrow down the actual cost of purchase and installation of these systems any further. Each home has different requirements and different climates to adapt to. They deliver savings over regular HVACs over the long-term, though.

These units bring your home to the desired temperature much quicker than traditional HVAC systems. They run less on average, saving on electric bills month to month.

While each home is different, the fact is that the flexible tubing doesn’t require extensive modification to install. Most of the time, alterations to the existing structure are very minimal. This can save money in contractor fees and construction fees.

Traditional HVACs have large and bulky ducts. Installing them in existing structures can require modifying the building. This can in turn drive up costs.

Blending In

When getting your unit set up, both SpacePak and Unico offer a full catalog of vent covers to help it fit into your home. These vents are designed to blend effectiveness with aesthetics. They come in multiple wood patterns to fit in with most wood flooring, as well as black, brass, and chrome variations.

If that’s not enough, all outlets can be painted or stained to match existing decor. If installed on the floor, the vents come equipped with a fine mesh grate to prevent items from falling down and obstructing the duct.

Check out Heil vs. Carrier: Which HVAC System Is Better?

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Related Questions

What maintenance do SpacePak and Unico systems need?

Clean the filter at least once per month, more if you live in a dusty area. While you’re at it, check the condensate traps and drains to make sure there are no blockages. Check your owner’s manual to see if your outside condensing unit requires lubrication for the fan and ensure that it remains free of debris.

What warranties do SpacePak and Unico have?

Both SpacePak and Unico have one-year limited warranties, effective from the installation. This is a standard warranty, and covers defects in the manufacturing process or workmanship. Both companies extend these warranties to five years if installed by a certified contractor in good standing.

Are SpacePak and Unico noisy?

An adequately installed High-Velocity HVAC should generate roughly the same amount of noise as a standard heating and cooling system. As long as it is installed with sufficient outlets, un-kinked supply tubing, and sound attenuator tubing, it should be almost unnoticeable. These systems have a reputation for noise, but that is nearly always the result of improper installation.

Wrapping Up

Ultimately, whether you choose SpacePak or Unico comes down to what is available in your area. Some areas will only have access to one, while other areas will only have representatives from the other. If both are available, we recommend Unico for the more straightforward installation. Additionally, take into account which product has a higher availability of replacement parts for future repairs.

As always, consult with a trained professional before making modifications to your home. Every home is different, and they can offer advice tailored to fit yours.

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Upgraded Home Team
Upgraded Home Team

We are a team of passionate homeowners, home improvement pros, and DIY enthusiasts who enjoy sharing home improvement, housekeeping, decorating, and more with other homeowners! Whether you're looking for a step-by-step guide on fixing an appliance or the cost of installing a fence, we've here to help.

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