New Systems for Granite Shoals, Sized to the House.
A new heating and cooling system is the biggest mechanical decision most Granite Shoals owners ever make, and the house gets more say in how it goes than any brochure does. A lake cottage that grew rooms needs a different plan than a newer build on one of the last open lots. So we start with a load calculation and a hard look at the ducts and the electrical panel, pick equipment after that, and the owner is on the truck when it goes in.
Sizing
The Math Comes Before the Model Number
Plenty of replacements get sized by reading the old unit’s label and ordering the same tonnage. That repeats whatever mistake was made the first time around, and in a house that has been added onto, the old number may have been wrong for decades.
A load calculation works from the house itself: the rooms and their size, the windows and which way they face, the insulation, the attic. Granite Shoals adds a few local pressures to that math. Granite outcrops in the yard store afternoon heat and hand it back through the evening. Lake humidity means the system has to wring moisture out of the air, and an oversized unit cools the rooms fast and shuts off before it dries anything, leaving the house cool and clammy at once.
How the house gets used matters too. A full-time household runs its system on an ordinary rhythm. A weekend place sits closed up for days, then has to come to comfort when the owners pull into the driveway, and a connected thermostat lets that happen on their schedule.
Where the outdoor unit will live gets planned at this stage too. Lake air wears on outdoor units faster close to the water, and a condenser wedged against sun-baked granite breathes hotter air all afternoon than one set out in the open. A spot with real clearance around it and a solid pad under it is a decision made once, and the system lives with that choice for as long as it runs. It also keeps the unit somewhere a tech can reach without a struggle, which matters the first time it needs service.
Only once those numbers are on paper does anybody start talking about brands.
Ducts
What the Ducts Have to Prove First
A good system on bad ducts runs loud and cools poorly. These get checked before anyone picks equipment.
Planning a Changeout This Year?
Tell us roughly how old the house is and what has been added on. The first visit is a free look, with the load and duct findings walked through in person.
A Cottage Built in Three Eras
No two streets here were built in the same decade. There are ranch houses from the middle of the last century, a handful of new homes going up on whatever lots were still empty, and the old lake cottages, many of which began life as somebody’s fishing place and kept sprouting rooms. The cottages are where installs get interesting. Every owner who added a room solved heating and cooling for that room alone, with whatever made sense that year. So one house can hold a window unit, a second system of a different age, and a thermostat that only knows about half the rooms, all running on one electric bill.
An install in a house like that begins with a map of what equipment exists, what each part of the house actually needs, and where the ducts go, including any run that got spliced in whenever a room went up. From there, one of two plans usually comes out ahead.
The first is a single right-sized central system with corrected ducts, so every era of the house gets real airflow. That can mean a new return, a reworked plenum, and swapping out the worst runs. It works well when ducts can reach every room without heroics.
The second is ductless. Each part of the house gets its own indoor head, sized to that space and piped to an outdoor unit through a line-set chase on the outside wall. The window units come out, the rooms stop competing, and nobody has to thread new duct through an attic that was never built for it.
Some houses end up with a mix of the two. You see the options side by side with prices, and the choice stays yours.
Every house like this is its own puzzle, and talking yours through costs nothing. A person picks up at (512) 925-3090 at any hour, and the contact page works for listing the additions first.
Diamond Contractor
Mitsubishi ductless systems, installed by a Diamond Contractor.
Second Generation
A family trade and ten years of Hill Country systems.
Owner on the Install
The owner is on the truck for the job.
Open 24 Hours
After install day, the phone still answers at any hour.
Diamond Contractor Ductless, and the Panel Behind It
Off Duty is a Mitsubishi Diamond Contractor, and in Granite Shoals that ductless work earns its keep. A room added long after the original system went in can get its own indoor head without anyone cutting open a finished ceiling to run duct. Each head runs as its own zone, so the people sleeping on one end of the house can keep it cool while the other end sits where everyone else likes it.
Before any new system goes in, the electrical panel gets a look. Plenty of houses here still run on the panel that went in when the place was a cottage with a window unit and a few lights. A new outdoor unit adds a real circuit, and backup heat strips on a heat pump add more. We check that the panel has the room and the capacity, and when it does not, you hear about it on the first visit, while the plan is still on paper.
On install day the old equipment comes out and the new system goes in to spec. Before the truck leaves, it runs under load while we read pressures and the temperature split and confirm the airflow matches the plan. Lake air is hard on outdoor units, so where the new one sits and what it sits on gets decided deliberately.
Some replacements come after a disaster. A Burnet family whose home took on damage in the July 2025 flood had their system replaced through a partnership with Samaritans Purse, and Cecilia A. wrote afterward: “Bryce is reputable and honest. Our home suffered a lot of damage in the 7/5/25 flood. Samaritans Purse partnered with Off Duty Heating and AC and replaced our heating and AC system. Couldn’t have asked for better care.” Photos of recent installs are in the gallery.
What Owners Ask Before a New System Goes In
Answers to what comes up during that first walk through the house.
Why not replace my old unit with the same size?
Because the old size may never have been right, especially in a house that has grown rooms since it was built. A load calculation measures what the house needs today. Copying the old label can leave you with a unit that short-cycles in lake humidity, or one that runs all afternoon and still loses the back bedroom.
Do I really need duct work along with a new system?
Not always. Static pressure, return size, and the condition of the reachable runs decide it. Some ducts are fine as they are. Many changeouts here get more out of a larger return or a rebuilt plenum than out of a pricier efficiency rating, and when that is true, it goes in the quote before equipment is ordered.
Our lake cottage has several additions. Central or ductless?
That depends on whether ducts can reach every part of the house without heroics. If they can, one right-sized system with corrected ducts is usually simplest. If the additions sit far from the equipment or have no path for duct, ductless heads for each area tend to win. Some houses get both, priced side by side.
Will an older electrical panel need work before the install?
Sometimes. Panels that predate modern loads may not have the space or capacity for a new outdoor unit and backup heat. We check the panel on the first visit, so any electrical need is part of the plan from the beginning. If work is needed, you hear exactly what it involves before you commit to anything.
We use the house on weekends. Does that change what gets installed?
It can. A house that sits closed for days benefits from a connected thermostat, so the system brings the place to comfort ahead of your arrival, and from freeze alerts in winter. Sizing still follows the load calculation, but the controls get chosen around how the house is actually lived in.
Once the new system is running, AC maintenance in Granite Shoals keeps its readings on file. If the old unit quits before install day, a repair visit or the after-hours line keeps the house livable, and our heat pump technicians cover the heating side later on. For more, see HVAC installation across the county, load calculations in depth, and the town page.
Start With a Free Look at the House
What does the free look cover? The load math, the ducts, and the panel, done on site before a single brand name comes up. Book it with the number below. Owners who would rather list the additions and the age of the house can do that on the contact page.
(512) 925-3090 Book a Free Look
