How to Choose a Furnace Supplier – 10 Questions to Ask

How to choose the right aluminium furnace supplier. 10 essential questions to ask before you buy. Based on 25 years of foundry experience.

Choosing a furnace supplier is not about finding the lowest price. It’s about finding a partner who will still be there when something goes wrong. And something always goes wrong.

I’ve spent 25 years buying, installing, and maintaining furnaces across Southeast Asia, India, the UK, and Europe. I’ve seen good suppliers and bad ones. The difference is rarely the equipment. It’s the support behind it.

Here are the 10 questions I ask every supplier before I recommend them to a client.

1. What is the guaranteed melt rate?

Every supplier claims their furnace melts fast. Ask for a guaranteed figure in tonnes per hour or kilograms per hour. Then ask under what conditions — cold charge, hot charge, what alloy, what charge mix.

A supplier who says “it depends” without giving a range is hiding something. A good supplier will give you a number and stand behind it.

I once saw a contract where the supplier guaranteed 1.5 tonnes per hour. The foundry ran it at 1.1 tonnes per hour. The supplier blamed the scrap quality. The contract didn’t specify scrap quality. That’s a lesson: get the guarantee in writing with conditions.

2. What is the energy consumption per tonne?

This is the number that determines your operating cost for the next 10 years. Ask for kWh per tonne for electric, or m³ per tonne for gas. Ask if it’s measured or calculated.

A foundry in Vietnam was quoted 550 kWh per tonne by one supplier and 750 kWh per tonne by another. The cheaper furnace used more energy. Over five years, the difference was $120,000. The “cheaper” furnace was actually more expensive.

3. What is the expected lining life?

The refractory lining is often the largest maintenance cost. Ask for expected life in months or tonnes melted. Ask what lining material they use and why.

If they say “it depends on operation,” ask for a reference site with similar operating conditions. Then call that reference. Don’t just take the supplier’s word.

I’ve seen linings last 18 months in one foundry and 8 years in another. The difference was installation quality and operating discipline. A good supplier will train your team on proper operation.

4. Can I visit a reference site in my region?

This is non-negotiable. If a supplier can’t show you a working installation within reasonable travel distance, that’s a red flag.

When you visit, don’t just look at the furnace. Talk to the maintenance team. Ask them:

• How often does it break down?
• How fast does the supplier respond?
• Would you buy from them again?

The answers will tell you more than any brochure.

I remember visiting a reference site in India where the maintenance manager said, “The furnace is fine. But spare parts take three months to arrive.” That single sentence changed my recommendation.

5. What is the lead time for spare parts?

Downtime is expensive. If a burner nozzle fails and you have to wait six weeks, you lose production. Ask for lead times on critical parts: burners, thermocouples, heating elements, refractory bricks.

A good supplier keeps a local stock of common parts. A bad supplier orders from overseas and makes you wait.

I always ask: “If I need a thermocouple tomorrow, can you deliver?” If the answer is no, I ask how much it costs to keep one on the shelf. Usually, it’s cheaper than a day of downtime.

6. What training do you provide for operators?

A furnace is only as good as the people running it. Ask what training is included. Is it on-site? How many days? Does it cover maintenance and troubleshooting?

I’ve seen foundries buy a good furnace and ruin it in six months because operators didn’t know how to control the temperature. Training is not optional.

A supplier in Europe included three days of on-site training with every furnace. Their clients had 40% fewer warranty claims. That’s not a coincidence.

7. What is the warranty and what does it cover?

Ask for the warranty period and exactly what’s covered. Does it include parts and labour? Does it cover the lining? Does it cover the burner?

Many warranties exclude the lining, which is the most expensive wear part. Ask specifically: “If the lining fails in year one, who pays?”

I’ve seen a foundry pay $15,000 for a lining replacement because the warranty excluded it. The supplier’s salesperson never mentioned that. Read the fine print.

8. Can you provide a total cost of ownership calculation?

A good supplier will help you calculate total cost over five years: purchase price, energy, maintenance, lining replacement, and downtime. If they can’t or won’t, they’re hiding something.

I do this calculation with every client. It often changes their decision. A furnace that costs 20% more upfront can save 30% over five years.

Ask for the calculation in writing. Then check the assumptions. Are energy prices realistic? Is downtime cost included?

9. What support do you offer after installation?

Installation is the beginning, not the end. Ask what happens after commissioning. Do they offer remote support? Do they have a local service engineer? How fast can they get to your site?

I worked with a foundry in Malaysia that had a supplier 3,000 km away. When the furnace broke, it took five days for an engineer to arrive. The foundry lost $50,000 in production.

Now, I always ask: “How many service engineers do you have in my country?” If the answer is zero, that’s a risk. It might still be acceptable, but you need to plan for it.

10. Can you provide a list of clients who left you?

This is the hardest question. Anyone can give you happy clients. But what about the ones who left? Why did they leave?

A good supplier will be honest. They might say, “We had a client who wanted a custom design we couldn’t deliver.” Or “We had a dispute over a warranty claim, and we resolved it this way.”

A bad supplier will refuse to answer. Or they’ll blame the client.

I’ve asked this question dozens of times. The answers have saved me from bad recommendations more than once.

A Real Case from Thailand

In 2023, a die casting plant in Thailand asked me to help choose a supplier. They had three quotes. All three looked similar on paper.

We asked the 10 questions. One supplier refused to provide a reference site. Another had no local spare parts. The third answered every question clearly and invited us to visit a factory in Vietnam.

We visited. The factory was clean. The maintenance team was happy. The supplier had a local warehouse with spare parts. They even had a client who had left them — and they explained why.

That supplier got the order. Two years later, the furnace is still running with zero unplanned downtime.

Final Thoughts

Choosing a supplier is not about finding the cheapest furnace. It’s about finding a partner who will support you for the next decade.

Ask the 10 questions. Visit the factory. Talk to the maintenance team. Check the spare parts. And don’t be afraid to ask the hard questions.

A good supplier will respect you for it. A bad supplier will walk away. Either way, you win.

Internal links: How to Choose the Right Aluminium Melting Furnace, Aluminium Melting Furnace Buying Guide 2026, New vs Used Aluminium Melting Furnaces,