Almost every homeowner who calls us about a new pool asks the same follow-up question within the first ten minutes: “Can we add a hot tub to it?” In Utah, that question makes more sense than almost anywhere else in the country. We have four real seasons, cold clear nights most of the year, and a culture built around being outside. A pool gets used three to four months a year. A pool and spa combo in Utah gets used twelve.

But a spa is not a small add-on you bolt onto a pool plan at the last minute. It changes your plumbing, your heating load, your equipment pad, your deck layout, and your monthly operating cost. Decisions you make in the first two weeks of design determine whether your spa becomes the most-used square footage on your property or an expensive water feature you look at from the kitchen window.

Here is what we walk our clients through before a single line gets drawn.

Attached Spa vs. Standalone Hot Tub: Two Very Different Purchases

The first fork in the road is whether you want a spa built into the pool structure or a portable acrylic hot tub set on a pad nearby. Both are legitimate choices, and the right answer depends on how you plan to use it.

The integrated (attached) spa

An integrated spa shares a wall with the pool and is built as part of the same monolithic structure. It typically sits 18 to 24 inches above the waterline, with a spillover edge that returns warm water into the pool. Advantages:

• It looks designed, not added. Same interior finish, same coping, same tile line — it reads as one composition instead of two objects.
• Shared equipment. One heater, one filter, one pad, one automation system, with valves that redirect flow between pool and spa modes.
• Better resale story. A built-in spa is real estate. A portable tub is personal property that may or may not stay with the house.
• Spillover matters more than people expect. That sheet of moving water is the single best sound feature you can add to a backyard, and it costs nothing extra to run when the spa is already circulating.

The standalone hot tub

Portable spas cost less up front, arrive pre-plumbed, and can be replaced in an afternoon. They also come with molded seating and higher jet counts than most custom spas. The tradeoffs are aesthetic and practical: a cabinet-clad box sitting near a custom pool rarely looks intentional, and you now have two separate systems to maintain, winterize, and pay for.

Our general guidance: if the spa is going to be used year-round and viewed from inside the house, build it in. If it is primarily therapeutic, needs deep contoured seating, or the budget is tight this year, put in the electrical and a level pad now and buy a portable unit later.

Heat Is the Real Cost — and Where Construction Method Decides the Bill

A pool is a big body of water that you heat occasionally. A spa is a small body of water that you heat constantly, often to 102°F, through January nights that drop into the teens along the Wasatch Front. That is a fundamentally different energy problem, and it is where the shell material you build with stops being an abstract detail.

Concrete and gunite are excellent structural materials and terrible insulators. A gunite spa is essentially a heated stone bowl set into cold ground, radiating warmth in every direction. Owners compensate with bigger heaters, tighter covers, and the acceptance that winter gas bills are simply what they are.

The Advantage Structural Foam (EPS) system we build with inverts that equation. The shell is formed from engineered expanded polystyrene blocks — the structure and the insulation are the same component, not a wrap added afterward. The result:

• Heat stays in the water instead of migrating into the soil. The insulating shell dramatically slows conductive loss, which is where most of a spa’s overnight temperature drop comes from.
• Shorter recovery times. Faster reheat means the spa is actually ready when you want it, not forty minutes from now.
• Smaller heating equipment does more work. You are not buying capacity just to overcome the shell.
• Real month-to-month savings. Insulation value compounds every single night for the life of the pool — and in a Utah winter, that is most nights.

We also finish the shell with a marble-clad interior over a waterproofing system that is rated for 40+ years, and the pool itself carries a 2-year warranty. For a spa specifically, that waterproofing rating matters: the thermal cycling of a heated basin is the harshest thing you can do to a pool surface, and cheap waterproofing is where cheap spas fail first.

Sizing and Seating: Get This Right or Nothing Else Matters

The most common regret we hear about spas is not cost. It is size.

An 8-person spa sounds generous until you realize it takes twice as long to heat, costs more to run, and you have used it with more than four people exactly twice. Meanwhile a spa sized for four is warm in minutes and gets used on a Tuesday in February.

Practical benchmarks

• 6–7 feet across comfortably seats four to five adults. This is the sweet spot for the overwhelming majority of families.
• 38–40 inches of depth gives you shoulder coverage while seated. Shallower and your shoulders get cold; deeper and smaller kids float off the bench.
• A bench, not a bowl. Continuous perimeter seating is more flexible than molded loungers and easier to keep clean.
• One dedicated lounge position is worth designing in if anyone in the household uses the spa therapeutically.

Also decide early where the spa faces. In Utah that usually means orienting toward the mountains, away from the neighbor’s second-story windows, and with the house behind you as a windbreak. Nobody wants a west-facing spa in a canyon breeze.

Plumbing, Jets, and Equipment Decisions People Skip

The mechanical package deserves as much attention as the shape:

• Dedicated spa pump. Sharing a single pump between pool circulation and spa jets is a compromise you will feel. Jets need pressure; circulation needs efficiency.
• Jet count discipline. More jets split the same pressure into weaker streams. Twelve well-placed jets beat twenty-four mediocre ones.
• Automation and remote control. The single biggest predictor of whether a spa gets used is whether it can be turned on from your phone on the drive home. Make this non-negotiable.
• An actual insulated cover. A safety cover is not a thermal cover. Budget for a real hard or high-R cover — it is the cheapest efficiency upgrade available.
• Freeze protection. In our climate, automated freeze-protect logic on the controller is essential, not optional.
• Separate chemistry. Hot water burns through sanitizer far faster than pool water. If you are running salt, confirm the system is rated for spa temperatures.

What It Costs to Add a Spa in Utah

An integrated spa built as part of a new pool typically adds a meaningful but predictable increment to the project — far less than building it as a separate phase later, because you are already mobilized, excavated, plumbed, and pouring. Adding a spa to a finished pool two years down the road commonly costs 40 to 60 percent more than including it in the original build, and you will be cutting into deck you already paid for.

Operating cost is the number people underestimate. A poorly insulated spa in a Utah winter can quietly become the most expensive appliance on your property. A well-insulated one is a rounding error on the gas bill. Same water, same temperature — different shell.

If you want to model your own project, our pool cost calculator lets you build a realistic budget range with and without a spa before you ever talk to a salesperson.

Permits, Barriers, and Safety

An integrated spa falls under the same barrier and safety requirements as the pool it is attached to, so if your pool enclosure is compliant, you are generally covered. A standalone hot tub is treated differently in most Utah jurisdictions — a locking hard cover meeting the applicable standard often substitutes for fencing, but this varies city by city, and your homeowner’s insurance may have its own requirements regardless of code. Confirm both before you buy.

A Short Checklist Before You Sign Anything

• Have you decided integrated vs. standalone — for reasons, not by default?
• Is the spa sized for who actually uses it, not the largest party you might host?
• Does the design include a dedicated spa pump and phone-based automation?
• Is there a real insulated cover in the budget?
• Do you know how the shell itself is insulated, and what that means for January?
• Is the spillover positioned where you will hear it from your seating area?

Build It Once, Build It Warm

A spa is the part of a pool project that pays you back in the months when the pool is covered. That only works if it is warm enough to be inviting, cheap enough to leave on, and close enough to the door that you will actually walk out there in the dark.

Those are design and construction decisions, not accessories. If you are planning a pool in Utah County, Salt Lake County, or anywhere along the Wasatch Front and want to talk through whether a spa belongs in your build, get in touch with our team. We build in structural foam because it is the right answer for our climate — and nowhere is that more obvious than in a spa that stays hot all winter.